Me Glo

TURBOSHAFT ENGINE
ASTAZOU
IV M1
MAINTENANCE
MANUAL
No. 288 02 936
Original issue: December 1980

Update No. 04: September 1995
64511 BORDES CEDEX - FRANCE - Tel.: 05.59.12.50.00 - Telex: 560928

Fax: (33) 05.59.53.15.12
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
INTRODUCTION
TABLE OF CONTENTS
Designation Chapter/Section Pages
General
- Presentation of manual 00-00-01 1 to 3

- Table of contents 00-00-02 1 to 18
The information included in this manual is covered

by the notice appearing on the information page 00 SeptemberPage
1991
1
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
INTRODUCTION
LIST OF EFFECTIVE PAGES
Chapter/Section Page Date Chapter/Section Page Date

00 1 Sept. 1991
2 Sept. 1991
00-00-01 1 May 1981

2 May 1981
3 May 1981
00-00-02 1 Sept. 1991

2 Sept. 1991
3 Sept. 1991
4 Sept. 1991
5 Sept. 1991
6 Sept. 1991
7 Sept. 1991
8 Sept. 1991
9 Sept. 1991
10 Sept. 1991
11 Sept. 1991
12 Sept. 1991
13 Sept. 1991
14 Sept. 1991
15 Sept. 1991
16 Sept. 1991
17 Sept. 1991
18 Sept. 1991

1991
2
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
GENERAL
PRESENTATION OF MANUAL
1. General
The present manual concerns the ASTAZOU IV M1 turboshaft engine. It consists of a manual
containing the description of the turboshaft engine and its accessories as well as instructions
indispensable for its maintenance. It is drawn up according to the specifications of Standard ATA 100.
2. Manual breakdown
The manual is broken down into the following chapters which are entirely or partially treated according
to the case:
- Chapter 5 - Periodicities
- Chapter 26 - Fire protection
- Chapter 70 - Standard practices
- Chapter 71 - Turbo-generator unit
- Chapter 72 - Turboshaft engine
- Chapter 73 - Fuel
- Chapter 74 - Ignition
- Chapter 77 - Engine indicating
- Chapter 78 - Exhaust
- Chapter 79 - Oil
- Chapter 80 - Startup
Each chapter begins with a table of contents followed by a list of pages validity making it possible for
the operator to ensure that its manual has been updated.
To facilitate search, pages concerning a well-defined turbo-generator unit component are numbered
according to the standard as follows:
- Description and operation Pages 1 to 100

- Trouble shooting Pages 101 to 200
- Maintenance operations (not subdivided) Pages 201 to 300
Maintenance operations (subdivided if necessary):
- Routine maintenance Pages 301 to 400

- Removal-Installation Pages 401 to 500
- Adjustment-Tests Pages 501 to 600
- Inspection-Checks Pages 601 to 700
- Cleaning-Paint Pages 701 to 800
- Authorized repairs Pages 801 to 900
Page 1
by the notice appearing on the information page 00-00-01 May 1981
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
With respect to trouble shooting procedures treated in chapter 72-00, only the following page
articulation has been adopted (101 to 200), which will enable easy addition of new sheets or
suppression of certain of them if necessary
- General Pages 101 to 110

- Ventilation Pages 111 to 120
- Ignition Pages 121 to 130
- Startup Pages 131 to 140
- Control Pages 141 to 150
- Operation Pages 151 to 160
- Lubrication system anomaly Pages 161 to 170
- Other anomalies Pages 171 and beyond
Furthermore, an alphabetical list is appended to this chapter for quickly locating the chapter, the
section and the page number in which the description of the main components, accessories and
operations is to be found.
Each page footer contains the chapter number to which it belongs, followed by two sets of numbers,
the first indicating the section number and the second the subject.
3. Utilization of manual
Two types of operations are implemented during turboshaft engine operation.
A. Mandatory maintenance operations
These operations are given in chapter 5 which is subjected to approval by Official Authorities.
B. Possible operations
These operations are performed following an incident or an operating fault. A general list in
chapter 00-00-02 details manual breakdown.
A table of contents placed at the beginning of each chapter resumes the sections and
sub-sections treated in the chapter.
It is thus easy to locate on one hand the chapter corresponding to the concerned engine part and
on the other the operation to be performed on this part.
CAUTION: ADJUSTMENTS GIVEN IN THIS MANUAL MUST ONLY BE

CARRIED OUT BY TURBOMECA PERSONNEL OR BY
SPECIALISTS HAVING UNDERGONE TRAINING AND
AUTHORIZED BY TURBOMECA.
Page 2
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
4. Update of manual
The update of the present manual will be carried out periodically, or when the engine evolution will
require it. These updates will be subjected to revisions each one assigned with a sequence number
indicating the date of the revision.
Revisions, addition, or deletion will be indicated using a vertical line in the left margin opposite the
modified sections, new sections or location of the deleted sections.
Page 3
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
GENERAL
TABLE OF CONTENTS
Breakdown Chapter
INTRODUCTION ........................................................................................................................ 00
GENERAL ........................................................................................................................... 00-00
Presentation of Manual ............................................................................................... 00-00-01

1. General
2. Manual breakdown
3. Utilization of manual
4. Manual update
Table of contents......................................................................................................... 00-00-02
HEALTH - SAFETY.................................................................................................................... 01-00
Hazards caused by electric currents........................................................................... 01-00-01

1. General
2. Prohibitions
Electric shock – First aid ............................................................................................. 01-00-02
1. General
2. Procedure
PERIODICITY............................................................................................................................. 05
GENERAL ........................................................................................................................... 05-00
Definitions.................................................................................................................... 05-00-01
INSPECTION ...................................................................................................................... 05-10
Implementation inspection .......................................................................................... 05-10-01

1. General
2. Inspection before operation
3. Starting instructions
4. Inspection during starting
5. Inspection after operation
Page 1
by the notice appearing on the information page 00-00-02 September 1991
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
Periodic inspections.................................................................................................... 05-10-02

1. General
2. Inspection every 50 hours of operation
5. Other inspections
FIRE PROTECTION .................................................................................................................. 26
GENERAL .......................................................................................................................... 26-00
General ....................................................................................................................... 26-00-01
Treatment after accidental triggering of an extinguisher on cold engine

1. General
2. Checks after fire extinguishing
3. Treatment after accidental triggering of an extinguisher on cold engine
FIRE DETECTION.............................................................................................................. 26-10
Detectors..................................................................................................................... 26-10-01
1. General
2. Description
3. Operation
4. Assembly
Maintenance operations
1. Routine maintenance
2. Removal-installation of detectors
FIRE EXTINGUISHING ...................................................................................................... 26-20
Equipment................................................................................................................... 26-20-01
1. General
2. Extinguisher
3. Pipes
4. Storage
2. Removal-installation of the extinguisher
Page 2
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
STANDARD PRACTICES.......................................................................................................... 70
GENERAL ........................................................................................................................... 70-00
General instructions .................................................................................................... 70-00-01

1. Precautionary measures
2. Disassembly
3. Cleaning
4. Inspection
5. Repair
6. Re-assembly
7. Inspection after intervention
ASSEMBLY......................................................................................................................... 70-10
General........................................................................................................................ 70-10-00
Hardware..................................................................................................................... 70-10-01
1. General
2. General precautions
3. Length of screws
4. High temperature screws
5. Removal of assembly hardware of hot parts
Tightening torque ........................................................................................................ 70-10-02
1. General
2. Tightening of assembly components using a torque wrench
3. Application procedure of tightening torques
4. Definition of locking and tightening torques
5. Assembling non-conventional attachments
6. Assembly conditions for normal attachments
Locking of assemblies................................................................................................. 70-10-03
1. General
2. Locking by self-locking nuts with internal packing
3. Locking by lock wire
4. Locking by lock plates
5. Locking by split pin
6. Locking by GROWER washer and tooth washer
7. Locking of slotted ruts
Page 3
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
STANDARD ASSEMBLY ................................................................................................... 70-20
General ....................................................................................................................... 70-20-00
O-rings ........................................................................................................................ 70-20-01

1. Inspection before assembly
2. Positioning O-ring using seal shank
3. Positioning O-ring without seal shank
4. Shelf-storage time of O-rings supplied as spares
Assembly of clamps.................................................................................................... 70-20-02
1. General
2. Assembly
Assembly of pipes....................................................................................................... 70-20-03
1. General
2. Inspection
3. Connectors equipping pipes
Assembly of standard connectors .............................................................................. 70-20-04
1. General
2. Inspection of connectors
3. Direct location connector
4. Link or union connector
5. Branch connector
6. Secondary branch connector
7. Special connector
8. Tightness
9. Assembly
10. Inspection of assembly
INSPECTION – TOUCH-UPS ............................................................................................ 70-30
Miscellaneous and touch-ups ..................................................................................... 70-30-01

1. General
2. Inspection methods
3. Checks to be performed on installed or removed assemblies
4. Minor repairs
5. Protection of repaired parts
Page 4
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
TURBO-GENERATOR UNIT ..................................................................................................... 71
GENERAL ........................................................................................................................... 71-00
Turbo-generator unit ................................................................................................... 71-00-01

1. General
2. Characteristics of ASTAZOU IV M1 turboshaft engine
3. Characteristics of turbo-generator unit
Installation ................................................................................................................... 71-00-02
1. Fuel supply
2. Oil supply
3. Electric power supply
4. Combustion air supply
5. Cooling air supply
6. Gas exhaust
7. Drain
8. Sampling
9. Cleaning and protection
1. Removal-installation of turboshaft engine
Fuel – Lubricants – Miscellaneous products............................................................... 71-00-03
1. General
2. Fuels
3. Lubricants
4. Miscellaneous products
Destorage – Storage ................................................................................................... 71-00-05
1. General
2. Short-term storage (ST)
3. Long-term storage (LT)
4. Storage - Packing of equipment
5. Shelf-storage time as a function of applied procedure
Page 5
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
ENCLOSURE ..................................................................................................................... 71-10
Package ...................................................................................................................... 71-10-01

1. General
2. Front frame
3. Rear frame
4. Side covers
5. Top cover
6. Bottom cover
7. Sleeve
1. Removal-installation of side cover
2. Removal-installation of bottom cover
3. Removal-installation of suction nozzle
STRUCTURE ..................................................................................................................... 71-20
Attachments and lifting ............................................................................................... 71-20-01

1. General
2. Attachment of engine unit
3. Transport
4. Lifting
CATCH LOCKS .................................................................................................................. 71-40
Structure assembly ..................................................................................................... 71-40-01

1. General
2. Description
ELECTRICAL EQUIPMENT............................................................................................... 71-50
Electrical harnesses.................................................................................................... 71-50-01

1. General
2. Starting harness
3. Control harness
4. Monitoring harness
5. Assembly of harnesses
1. Removal–installation of electrical harnesses
Page 6
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
DRAINS............................................................................................................................... 71-70
Equipment ................................................................................................................... 71-70-01

1. General
2. Description
TURBOSHAFT ENGINE ............................................................................................................ 72
GENERAL ........................................................................................................................... 72-00
Composition of engine ................................................................................................ 72-00-01

1. Description
2. Operation
Trouble shooting
1. General
2. Ventilation
3. Ignition
4. Engine control
5. Operation
6. Lubrication system anomaly
7. Other anomalies
POWER DRIVE .................................................................................................................. 72-10
General........................................................................................................................ 72-10-00
Connection casing....................................................................................................... 72-10-01

1. General
2. Description
1. Removal-installation of connection casing
Torque limiter .............................................................................................................. 72-10-02
1. General
2. Description
3. Operation
1. Removal-installation of torque limiter
2. Adjustment of torque limiter
Page 7
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
Reduction gearbox...................................................................................................... 72-10-03

1. General
2. Operation
3. Hub casing
4. Driving pinion
5. Output wheel
6. Intermediate pinion assembly
7. Installed assembly and accessories
AIR INLET .......................................................................................................................... 72-20
General ....................................................................................................................... 72-20-00
Air inlet casing ........................................................................................................... 72-20-01

1. General
2. External view
3. Sectional view
Spraying manifold ....................................................................................................... 72-20-02
1. General
2. Installation
1. Washing of air path
2. Protection of air path
COMPRESSION................................................................................................................. 72-30
General ....................................................................................................................... 72-30-00
Compressor counter-casing ....................................................................................... 72-30-01

1. General
2. Description
Axial compressor ........................................................................................................ 72-30-02
1. General
2. Mobile part
3. Fixed part
4. Assembly and operation
5. Coupling sleeve
Page 8
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
Centrifugal compressor ............................................................................................... 72-30-03

1. General
2. Mobile part
3. Fixed part
4. Assembly of centrifugal compressor
5. Coupling sleeve
COMBUSTION.................................................................................................................... 72-40
General........................................................................................................................ 72-40-00
1. General
2. Mobile part
Turbine casing............................................................................................................. 72-40-01
1. General
2. Description
3. Assembly
4. Purge valve
1. Check of purge valve operation
2. Removal-installation of purge valve
Combustion chamber .................................................................................................. 72-40-02
1. General
2. External mixer
3. Internal mixer
4. Labyrinth
5. Assembly of combustion chamber
6. Air flow
TURBINES .......................................................................................................................... 72-50
General........................................................................................................................ 72-50-00
Shielding...................................................................................................................... 72-50-01
1. General
2. Description of shielding
Turbine ........................................................................................................................ 72-50-02
1. General
2. Fixed part
3. Mobile part
4. Assembly and operation of turbine
1. Check of play in 3rd stage turbine
Page 9
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
Diffuser bearing .......................................................................................................... 72-50-03

1. General
2. Exhaust diffuser
3. Rear bearing
4. Rear bearing assembly
1. Crack inspection
ACCESSORY DRIVE ......................................................................................................... 72-60
General ....................................................................................................................... 72-60-00
Pinion system ............................................................................................................. 72-60-01

1. General
2. General operation
3. Governor drive pinion
4. Governor intermediate pinion
5. Oil pump drive pinion
6. Starter intermediate pinion
Relay box .................................................................................................................... 72-60-02
1. General
2. Description
3. Operation
4. Assembly of relay box
2. Removal–installation of relay box
LUBRICATION ................................................................................................................... 72-80
General ....................................................................................................................... 72-80-00
System operation ....................................................................................................... 72-80-01

1. General
2. Description – Operation
1. Inspection of particles in oil
2. Check of dilution rate
3. Protection of lubricated areas
Page 10
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
Oil tank casing............................................................................................................. 72-80-02

1. General
2. Description
2. Draining of oil tank casing
3. Oil level check
4. Filling of oil tank casing
5. Rinsing oil system
Lubrication unit ........................................................................................................... 72-80-03
1. General
2. Oil pump
3. Oil filter
4. Operation and safety accessories
5. Oil flow in lubrication unit
6. Lubrication unit equipment
2. Removal-installation of oil filter
3. Removal-installation of strainer
4. Removal-installation of lubrication unit
5. Removal of magnetic plug
Internal ducts............................................................................................................... 72-80-04
1. General
2. Lubrication of reduction gearbox area
3. Lubrication of central bearing
4. Lubrication of rear bearing
5. Lubrication of relay box
6. Lubrication of control unit
Pipes ........................................................................................................................... 72-80-05
1. General
2. Internal pipes
3. External pipes
Page 11
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
FUEL SYSTEM .......................................................................................................................... 73
FUEL SYSTEM................................................................................................................... 73-00
Authorized fuel ............................................................................................................ 72-00-01

Specification
(see chapter 71-00-02)
Description of system ................................................................................................. 73-00-02
1. General
2. Breakdown of fuel system
3. Operation of fuel system
4. Sequential operation of engine
1. Protection of system
IGNITION SYSTEM............................................................................................................ 73-10
Injectors ...................................................................................................................... 73-10-01

1. General
2. Description
3. Operation
4. Assembly
2. Removal-installation of a fuel injector
3. Check of an injector
4. Cleaning of an injector
STARTUP SYSTEM ........................................................................................................... 73-20
Startup unit.................................................................................................................. 73-20-01

1. General
2. Servovalve
3. Operation of startup unit
4. Description of startup unit
5. Attachment of startup unit
2. Removal-installation of startup unit
Page 12
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
MAIN SYSTEM ................................................................................................................... 73-30
Fuel control unit........................................................................................................... 73-30-01

1. General
2. Fuel pump
3. Pressure relief valve and pressure intake
4. Oil pump
5. Speed detector and oil distributor
6. Speed control indicator
7. Fuel metering valve control system
8. Fuel metering valve
9. Electric motor assembly
10. Microswitch unit
11. Adjustable static system
12. Constant ∆p system
13. Control shaft
14. Handle shaft
15. Oil bypass and pressure intake
16. Oil check valve
17. Fuel control unit operation at different rates
18. Assembly and fuel control unit equipment
19. Fuel control unit attachment
2. Removal-installation of fuel pump pressure relief valve
3. Removal-installation of fuel control unit oil pump pressure relief valve
4. Removal-installation of fuel control unit
5. Removal-installation of fuel metering valve
6. Adjustment of speed limit stops
FUEL SYSTEM EQUIPMENT............................................................................................. 73-40
Internal parts ............................................................................................................... 73-40-01

1. General
2. Fuel tube
3. Injector connector
4. Injection wheel
5. Driving of fuel tube
1. Removal-installation of fuel injector connector
2. Cleaning of injection wheel
Page 13
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
Solenoid valves........................................................................................................... 73-40-02

1. General
2. Description
3. Operation
4. Assembly and equipment
2. Removal-installation of solenoid valve coils
3. Removal-installation of solenoid valves
Accessories ................................................................................................................ 73-40-03
1. General
2. Description
Pipes ........................................................................................................................... 73-40-04
1. General
2. Internal pipes
3. External pipes
2. Removal-installation of filtering element of fuel filter
IGNITION ................................................................................................................................... 74
ELECTRICAL GENERATION ............................................................................................ 74-10
High energy generator ................................................................................................ 74-10-01

1. General
2. Description
3. Operation
4. Assembly
1. Removal-installation of generator units
Page 14
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
DISTRIBUTION................................................................................................................... 74-20
Igniters......................................................................................................................... 74-20-01
1. General
2. Description
3. Operation
4. Assembly
2. Removal-installation of igniters
Igniter cables ............................................................................................................... 74-20-02
1. General
2. Description
2. Removal-installation of igniter cables
ENGINE INDICATING................................................................................................................ 77
ROTATION SPEED INDICATION ...................................................................................... 77-10
Magnetic sensor .......................................................................................................... 77-10-01

1. General
2. Description
3. Operation
4. Assembly
2. Removal-installation of magnetic sensor
Page 15
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
TEMPERATURE T4 INDICATION ..................................................................................... 77-20
Pyrometric harness..................................................................................................... 77-20-01

1. General
2. Thermocouple
3. Connection unit
4. Assembly of harness
2. Check of a thermocouple
3. Removal-installation of a thermocouple
4. Removal-installation of pyrometric harness
5. Replacement of homogenisation resistor
Thermal probe ............................................................................................................ 77-20-02
1. General
2. Description
3. Operation
4. Assembly
2. Removal-installation of thermal probe
EXHAUST .................................................................................................................................. 78
EXHAUST........................................................................................................................... 78-10
Nozzle ......................................................................................................................... 78-10-01

1. General
2. Description
3. Assembly
1. Removal-installation of nozzle
Page 16
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
EXTERNAL OIL SYSTEM ......................................................................................................... 79
ACCESSORIES .................................................................................................................. 79-10
Oil cooler ..................................................................................................................... 79-10-01

1. General
2. Description
3. Operation
4. Equipment
5. Assembly
2. Removal-installation of oil cooler
PIPES.................................................................................................................................. 79-20
CHECK................................................................................................................................ 79-30
General........................................................................................................................ 79-30-00
Oil pressure check: pressure switches ....................................................................... 79-30-01

1. General
2. Description
3. Operation of low oil pressure switch
4. Operation of load pressure switch
5. Equipment
6. Assembly
1. Removal-installation of the pressure switch
Oil temperature check ................................................................................................. 79-30-02
1. General
2. Probe
3. Thermal switch
4. Assembly
2. Removal-installation of probe
3. Removal-installation of thermal switch
Page 17
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Composition Chapter
STARTUP .................................................................................................................................. 80
SETTING INTO ROTATION............................................................................................... 80-10
Starter ......................................................................................................................... 80-10-01

1. General
2. Description
3. Assembly
2. Removal-installation of starter
Page 18
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
HEALTH - SAFETY
TABLE OF CONTENTS
Hazards caused by electric currents 01-00-01 1
Electric shock - first aid 01-00-02 1 to 5
THIS CHAPTER IS NOT OF TURBOMECA'S

RESPONSIBILITY. IT HAS BEEN INTRODUCED IN
THIS MANUAL UPON FRENCH MARINE REQUEST.
Page 1
by the notice appearing on the information page 01 December 1983
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
HEALTH - SAFETY

01 1 Dec. 1983
2 Dec. 1983
01-00-01 1 Dec. 1983
01-00-02 1 Dec. 1983

2 Dec. 1983
3 Dec. 1983
4 Dec. 1983
5 Dec. 1983
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by the notice appearing on the information page 01 December 1983
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
HAZARDS CAUSED BY ELECTRIC CURRENTS
1. General
In order to operate, this equipment needs high voltages and these are potentially deadly. A voltage of
110 V can cause death. Personnel should at all times comply with all safety requirements.
2. Prohibitions
- Never change a thermionic tube without first having switched off the high voltage power supply.
- Be careful with safety systems such as circuit breakers or slide-valve and door devices. Check
whether the safety systems have operated properly. Where possible, switch off power supplies
before carrying out any operation inside the device.
- Never forget that safety devices are provided only on normal accesses and that dangerous circuits
may be formed as a result of dismantling work.
- In certain cases dangerous voltages may still exist after the device has been switched off owing to
the charges retained by the capacitors. It is therefore necessary to take the precaution of
discharging them prior to carrying out any operations inside the device.
WARNING: IT IS PROHIBITED TO ENTER A ROOM ALONE FOR THE

PURPOSE OF CARRYING OUT INSPECTIONS OR REPAIRS ON
HAZARDOUS EDUIPMENT.
Page 1
by the notice appearing on the information page 01-00-01 December 1983
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
ELECTRIC SHOCK - FIRST AID
1. General
Anyone who installs, operates or maintains this piece of equipment must familiarise himself with the
following rules which are both THEORETICAL and PRACTICAL in nature. It is the DUTY of each and
everyone to be ready to administer first aid treatment so that human Iife is not lost. YOUR LIFE
DEPENDS ON IT.
Generally speaking, an electric shock DOES NOT KILL IMMEDIATELY, the victim can be saved even if
HE IS NO LONGER BREATHING.
2. Procedure
Step one: move the victim away from the electrical system:
Use a dry non conducting material (rubber gloves, cloth) to remove either the electric wire or the victim.
Do not use metallic or wet materials. If the voltage is more than 1,000 V, cut off the current and take
appropriate action to break the victim's fall.
If it is not possible to switch the current, stand on an insulated stool and use a dry non conducting pole
to remove the wire from the victim. The wire must not touch the victim's face or other exposed parts of
the body.
Once the victim has been moved away from the electrical system. Do not try to move him and
administer first aid immediately. Stretch the victim on his back.
Loosen his clothes collar tie etc.
Remove any foreign matter which may be present in his mouth (tobacco, dentures etc ) with your
fingers.
Step two: if the victim has stopped breathing
Perform mouth to mouth resuscitation immediately.
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TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
"MOUTH TO MOUTH" RESUSCITATION
Figure 1 – Artificial resuscitation by a single lifesaver
1) Kneel down next to the victim's head and preferably on his left.
2) Tilt the victim's head back. This operation is of the almost importance since it is vital in order to
clear the victim's respiratory tract.
To do this, put your left hand under the victim's neck and lift, the victim's head will fall back. Pinch
the victim's nose with your right hand. Use the palm of your hand to keep the victim's head tilted by
resting it on his forehead.
3) After breathing in deeply, put your open mouth to the victim's mouth and breathe out (vigorously)
until the victim's chest expands.
Then remove your mouth to allow the victim to passively exhale the air he has received (by
spontaneous elastic contraction of his chest).
Page 2
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
4) Air should be given to and withdrawn from the victim in this way approximately 12 times per minute
until the victim starts to breathe properly and in a stable manner.
Step three: if the victim's heart has stopped breathing:
- No pulse can be defected at the major arteries (femoral, carotid arteries).

- Mouth to mouth resuscitation should be combined with:
EXTERNAL HEART MASSAGE
1) THEORY:
The thorax which is rigid and resistant in a normal subject, becomes limp and flexible in an
unconscious subject.
In these circumstances, pressure exerted on the rib cage compresses the heart against the bony
dorsal skeleton and removes blood present in the heart. When pressure on the thorax is released,
the heart which is a flexible organ dilates and fills with blood of its own accord.
2) PRACTICE: See Figure 2
Figure 2– External chest massage by a single lifesaver
Page 3
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
- Victim stretched out in the supine position on a rigid surface (on the ground)
- Kneel down next to the victim at right angles to the trunk of the victim's body. Cross your
hands one on top of the other and place them flat on the bottom third of the victim's sternum
right in the middle of the thorax. Using your hands, depress the victim's sternum rapidly and
vigorously by about 4 to 5 cm and release the pressure straightaway.
- The rate of compression is 60 times per minute i.e. one pressure stroke per second or 5
thoracic compressions for one series of mouth to mouth resuscitation.
- Although tiring for the Iifesaver, this operation must be continued until the victim's heart starts
beating again.
3. Important remarks:
- Compression of the thorax should be strictly in the median plane.

- External heart massage is very effective and can ensure adequate circulation for one or more
hours.
- Regular compression of the thorax ensures circulation, respiration will be ensured by combining
this form of treatment with mouth to mouth resuscitation preferably performed by a second
lifesaver (Figure 3).
Figure 3 - The lifesaver on the right performs external heart massage,

the lifesaver on the left performs mouth to mouth resuscitation
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Step four: take the victim to the resuscitation centre
- Without interrupting the two procedures described above, external heart massage and artificial
mouth to mouth resuscitation, it is necessary to get the victim to the Resuscitation Centre as
soon as possible.
- The victim should be taken by ambulance at the very low speed of 10 mph. The aim behind
this, is to enable the lifesavers to continue administering the two essential forms of treatment
described above the victim and to avoid distressing the latter.
- These forms of first aid treatment are highly effective if carried out correctly and with
perseverance, however describing them in written form is generally not enough to enable their
correct application; a practical first aid training course is indispensable for all the personnel
involved.
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PERIODICITIES
TABLE OF CONTENTS
General
- Definitions 05-00-01 1
Inspection
- Implementation inspections 05-10-01 1 and 2

- Periodic inspections 05-10-02 1 and 2
Page 1
by the notice appearing on the information page 05 May 1981
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
PERIODICITIES

05 1 May 1981
2 Sept. 1995
05-00-01 1 May 1981
05-10-01 1 Dec. 1983

2 Sept. 1991
05-10-02 1 Sept. 1991

2 Sept. 1995
Page 2
by the notice appearing on the information page 05 September 1995
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
GENERAL
DEFINITIONS
Inspection operations can be classified into three groups:
- Implementation inspections.
- Periodic inspections.
- Possible inspections or maintenance operations.
Implementation inspections consist of inspections after operation and before operation.
Periodic inspections are Iinked to engine operating time. The recommended periodicities for the
engine and its accessories are indicated as theoretical values which can be modified (increased or
reduced) according to the experience acquired during its operation.
If experience acquired during operation of the engine on the alternator results in modifying inspection
periodicities and that the difference between the new periodicity provided by the engine manufacturer
and that provided for the alternator exceeds 25%, the engine manufacturer's agreement is required
before deciding on integrating the inspection in question in one or the other periodicity of the
alternator.
Possible inspections or maintenance operations take place outside scheduled periodic inspections
when an unforeseen incident was indicated by the user or the operator or yet following use of the
turbo-generator under certain conditions.
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INSPECTION
IMPLEMENTATION INSPECTIONS
1. General
The implementation inspections include:
- inspection before operation,

- inspection during starting,
- inspection after operation.
2. Inspection before operation
The purpose of this inspection is to ensure that the engine which may have undergone emergency
repair interventions following an inspection after operation has remained in operating condition.
This inspection takes place as follows:
- check tightening of various pipes,

- check connection of electrical connectors,
- check condition and attachment of electric cables,
- check attachment of accessories on engine,
- check attachment of turboshaft engine,
- check cleanliness of engine and the bottom part of the enclosure,
- check that the general drain is not clogged,
- check oil level (carry out one or two ventilation operations prior to this check).
3. Instructions for startup
ALWAYS PRECEDE A STARTUP OPERATION BY A VENTILATION OPERATION.
- If residual temperature t4 is greater than 100 °C:

- do not attempt to start up,
- carry out one or two ventilation operations to lower the temperature,
- or wait until the turboshaft engine has naturally cooled down.
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4. Inspection during startup
As soon as startup takes place, this inspection determines the condition and attachment of the engine
accessories and pipes.
- check for absence of leaks at the various oil and fuel pipe connectors,
- check for absence of leaks at the level of mating faces of the engine and accessories.
5. Inspection after operation
On engine shutdown, check for flow through the injection wheel draining. When stopping is selected,
make sure that the duration of draining is 10 seconds and that of the blower is 60 seconds.
After operation, the engine must be returned to a condition which allows another operation without
intervention. Inspection therefore mainly consists in searching for a possible operating fault.
Carry out this inspection within the half-hour following engine shutdown (cooling or oil system
stabilization):
- check oil level and top up if necessary,

- perform a ventilation operation,
- check for absence of abnormal noises: rubs or bearing deterioration,
- measure the rundown time,
- perform compressor washing if necessary.

by the notice appearing on the information page 05-10-01 SeptemberPage
1991
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MAINTENANCE MANUAL
INSPECTION
PERIODIC INSPECTIONS
1. General
A. Maintenance cycle
The maintenance cycle is based on engine operating hours.
Four types of inspections are scheduled, 50, 250, 500 and 1,000 hours of operation. Inspections
of higher order include all the operations defined and those for each lower order inspection. For
example, inspection for 500 hours of operation includes, in addition to its own operations, those of
inspection for 50 hours and 250 hours of operation.
B. Tolerance for operation execution
In order to give a certain flexibility for organizing periodic maintenance work, a tolerance of ± 10%
hours is applicable to their implementation frequency.
Operation Chapter
Compressor cleaning 72-20-02
NOTE: The compressor cleaning operation can take place before each 50 hour inspection.
Operations Chapter
Check of oil filter 72-80-03
Cleaning of strainer 72-80-03
Cleaning of injection wheel 73-40-01
Check of dilution rate 72-80-01
Visual inspection of thermocouples 77-20-01

1991
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Operation Chapter
Replacement of oil filter cartridge 72-80-03
Replacement of fuel filter cartridge 73-40-04
Replacement of ignition injectors 73-10-01
Check of 3rd stage turbine wheel play 72-50-02
Cleaning of purge valve 72-40-01
Checking of igniters 74-20-01
Electric check of thermocouples 77-20-01
NOTE: The accessories provided for replacement can be cleaned and re-used if necessary.
5. Inspection every 1,000 hours of operation
Replacement of igniters, if necessary, after inspection (see 74-20-01, page 203), otherwise
replacement during the 50 hour inspection, if the igniters condition requires it.
6. Other inspections
Operation Chapter
Check of internal pressure of tank every month 26-20-01
Weighing of extinguisher assembly every six 26-20-01

months
Replacement of electro-pyrotechnic cartridge 26-20-01

every three years
Overhaul of tank assembly every five years 26-20-01

1995
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MAINTENANCE MANUAL
FIRE PROTECTION
TABLE OF CONTENTS
Fire protection
- General 26-00-01 1
- Treatment after use of
extinguishing agent 201 to 204
Fire detection
- Detectors 26-10-01 1 to 3
- Maintenance operations 201 and 202
Fire extinguishing
- Equipment 26-20-01 1 to 3
- Maintenance operations 201 to 203
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PERIODICITIES

26 1 Sept. 1991
2 Sept. 1995
26-00-01 1 Sept. 1995
201 Sept. 1995

202 Sept. 1991
203 Sept. 1991
204 Sept. 1991
26-10-01 1 Dec. 1983

2 May 1981
3 May 1981
201 May 1981

202 May 1981
26-20-01 1 Sept. 1991

2 Sept. 1991
3 Sept. 1991
201 Sept. 1991

202 Sept. 1995
203 Sept. 1991
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FIRE PROTECTION
GENERAL
1. General
The on board fixed installation is equipped with HALON 1301 extinguishers, non-corrosive for cold
parts and non toxic. Nevertheless, for fire fighting, other products can be regularly used such as:
- carbon gas (carbon dioxide),

- chemical or physical foams,
- dry powders,
- halogen based products.
CAUTION: SOME OF THESE PRODUCTS BECOME CORROSIVE WHEN IN CONTACT

WITH HOT PARTS AND CAN PRODUCE DEPOSITS RESULTING IN CLOGGING:
THIS IS WHY THE ENGINE MUST BE CLEANED AS QUICKLY AS POSSIBLE.
WARNING: SOME OF THESE PRODUCTS CAN ALSO BE TOXIC BY BREATHING

IN OR THROUGH THE SKIN; THIS IS WHY THE FOLLOWING
SANITARY PRECAUTIONS MUST BE TAKEN.
- AVOID BREATHING IN VAPORS; THEY CAN BE DANGEROUS EVEN

IN SMALL QUANTITIES.
- ENSURE MAXIMUM VENTILATION OF THE WORK AREA.
- AVOID DIRECT CONTACT WITH THE EXTINGUISHING PRODUCT,

WEAR RUBBER GLOVES.
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FIRE PROTECTION
TREATMENT AFTER USE OF AN EXTINGUISHING AGENT
1. General
Two cases can occur:
A. Treatment after extinguishing a fire or after accidental triggering of an extinguisher on hot engine
(stopped since less than 10 minutes).
B. Treatment after accidental triggering of an extinguisher on cold engine.
2. Checks after fire extinguishing
The following procedures apply to equipment considered in operational condition or which can be
returned to operational condition on site.
A. After use of carbon gas
(1) Effects of C02
Since carbon gas is inert and non corrosive and evaporates without leaving traces, its use
does not require any treatment for the engine.
Nevertheless its expansion can, by thermal shock, cause crack formation on hot parts
(turbine casing - exhaust diffuser).
(2) Checks after using C02
a) Check for absence of cracks on:
- turbine casing (para 72-40-01),

- exhaust diffuser (para 72-50-03).
b) Actions
- In the event of crack formation or product penetration in the air inlet (engine running).
- Remove engine (para 71-00-02 pages 201 to 203) for return to factory (specify type
of shipment).
- Otherwise
• Replace damaged equipment.
• Ground run (nominal speed at no load for 5 min).
• Check that there are no leaks then replace bad seals.
• Keep the equipment in operation.
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B. After use of foam
(1) Effects on engine
Chemical foam (reaction of an acid with a carbonate in the presence of water and a foaming
agent,
or physical foam (water under pressure + foaming agent + ambient air) can result in
corrosion and form deposits.
(2) Treatment of engine
a) Clean with water added with detergent and degreasing product then carefully rinse.
b) Check electrical harnesses; if necessary, disconnect connectors and dry them with hot
air (maximum 80 C).
c) Clean venting pipe of the rear bearing.
(3) Actions
Refer to subdivision 2. A. 2) b) of this chapter.
C. After use of dry powder
Dry powders (basic products: sodium bicarbonate or potassium) can corrode, clog or form
glazed deposits on hot parts.
a) Using a vacuum cleaner, remove the powder which can be accessed.
b) Then perform the operations described in subdivision 2. B. 2).
(3) Actions
Refer to subdivision 2. A. 2) b) of this chapter.
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D. After use of HALON
A HALON (HALOGENATED HYDROCARBON) in the form of a volatile liquid or a colorless

and odourless gas is a hydrocarbon derivative containing halogene compounds (Fluoride
Bromium Chlorine):
Example: Tribromofluoride (TBF)

Bromotrifluoromethane (BTM or HALON 1301)
Bromochlorodifluoromethane (SCF or HALON 1211)
Bromochloromethane (BCM or HALON 1311).
Generally, these are inert on cold parts but become corrosive on contact with hot parts and
can deteriorate silicone based products (exhaust bellows).
CAUTION: WATER INCREASES THE CORROSIVE ACTION OF HALONS BY

FORMING ACIDS AFTER USE OF A LIQUID HALON. NEVER USE
WATER FOR WASHING TO REMOVE THE PRODUCT.
a) It is recommended to treat the engine immediately after using a HALON, observing the
following sanitary instructions:
WARNING: SOME OF THESE PRODUCTS CAN ALSO BE TOXIC BY

BREATHING IN OR THROUGH THE SKIN. THIS IS WHY THE
FOLLOWING SANITARY PRECAUTIONS MUST BE TAKEN.
- AVOID BREATHING IN VAPORS, THEY CAN BE
DANGEROUS EVEN IN SMALL QUANTITIES.
- ENSURE MAXIMUM VENTILATION OF THE WORK AREA.
- AVOID DIRECT CONTACT WITH THE EXTINGUISHING
PRODUCT, WEAR RUBBER GLOVES.
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b) If necessary, use a sponge to remove liquid traces.
c) As soon as possible, start up the engine and let it turn at nominal speed and no-load for
5 minutes.
NOTE: If startup is impossible within the hour following fire extinguishing,

externally dry the engine using a jet of hot air (80 °C max.).
(3) Actions
a) Refer to subdivision 2. A. 2) b) of this chapter.
b) Check the condition of the exhaust bellows after engine operation.
3. Treatment after accidental triggering of an extinguisher on cold engine
A. After use of carbon gas
(1) No treatment.
(2) Keep the engine in operation.
B. After use of foam
(1) Treatment: ditto 2. B. 2).
C. After use of powder
(1) Treatment ditto 2. C. 2).
D. After use of a HALON
(1) Treatment ditto 2. D. 2).
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FIRE DETECTION
DETECTORS
1. General
Following accidental leakage of fuel or oil in hot areas of the engine, fire can break out. It is immediately
indicated by three detectors located at points which are most appropriate for this risk.
2. Description (Figure 1)
Each detector consists of two twin blades (1) and (2), one of which (1) is heat insulated. These twin
blades are equipped on their top section with pellets (4) which ensure electrical contact between each
other. Each of them is connected to an electric connection terminal (10), between these terminals an
electric resistance is connected, enclosed in a ceramic insulated terminal protector (9).
The twin blades are protected by a body (6) comprising four holes (7) through which air flows. The
end of this body is equipped with a stop (3) and an adjustment screw (5). A triangular receptacle (8)
drilled with 3 holes is used for securing the detector. Two nuts (11) are used for connecting power
supply cables.
Figure 1 – Detector
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3. Operation
The detectors are adjusted to trigger an electric signal as soon as the ambient air exceeds 300 °C.
They also indicate a sudden temperature rise even if it does not exceed 300 °C.
A. Overheating
A progressive temperature rise causes expansion of the twin blades which move almost at the
same speed, while preserving electric contact. As soon as the limit temperature is reached, the
rear twin blade hits against the limit stop which continues its travel, until the electric contact,
caused by separation of the pellets. The electric current then passes through the resistance which
causes current intensity variation and producing the signal.
B. Fire
In the presence of flames, there is a sudden temperature rise causing almost instantaneous
deformation of the front twin blade, before the rear twin blade has time to react. Thus the contact
is broken immediately producing the signal.
C. End of alarm
In both cases, the detectors give an end of alarm when the heat source has disappeared.
4. Assembly (Figure 2)
The three detectors (7) are secured on three supports. The first (5) is held by the lubrication unit,
blanking plate, attachment screws (6) and the two others (2) by the exhaust diffuser attachment screws
(1). These supports are equipped with three crimped nuts (3) which receive detector attachment
screws (4).
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Figure 2 - Detector
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FIRE DETECTION
MAINTENANCE OPERATIONS
A. Check attachment of detectors.
B. Check attachment of electric cables to detector terminals as well as condition and attachment of
monitoring harness.
C. Check external aspect of each detector as well as condition of insulating body.
D. Ensure that the twin blade contacts are well pressed against each other.
NOTE: It is forbidden to touch the twin blades or their contact. This type of detector cannot
be repaired, it should be replaced in the event of an anomaly.
2. Removal – Installation of detectors
A. Purpose
- Replacement of a detector in the event of an operation anomaly.

- Removal of lubrication unit on which one of the detectors is secured.
B. Means required
(1) Possible spares
Fig. Item Designation IPC Chap. Fig. Item
201 3 Fire detector 26-11 1 5
C. Preliminary steps
(1) Remove the bottom cover of the detector located on the lubrication unit.
(2) Remove the left hand side cover from the other two detectors.
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D. Removal (Figure 201)
(1) Unscrew nuts (1), remove lugs of electric conductors (2) from detector terminals along with
washers (9).
(2) Remove the three attachment screws (8), recover their washers (7) and remove the
detector (3).
E. Installation
(1) Place the detector (3) on its support (4). Position it by inserting boss (5) of the support in
notch (6) of the triangular receptacle of the detector. Position and tighten screws (8) fitted
with their washers (7).
(2) Place the lugs of electric conductors (2) framed with washers (9) (the conductor is identified
by the red sleeve on the long terminal). Screw in and tighten nuts (1).
+2
- Tightening torque: 18 cm daN
+0
F. Reconditionning
(1) Install the left hand side cover.
(2) Install the bottom cover.
Figure 201 – Removal of fire detector
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FIRE EXTINGUISHING
EQUIPMENT
1. General
The ASTAZOU IV M1 turboshaft engine comprises an electrically controlled system for extinguishing
any fire detected and indicated by the detectors.
2. Extinguisher (Figure 1)
The extinguisher is a spherical tank (3) filled with a gaseous refrigerating mixture consisting of
pressurized freon and nitrogen.
Filling is performed through a safety orifice (6) fitted with a blanking plug (5). A pressure gauge (11)
indicates filling pressure.
The percussion head composed of a discharge head (8) and a pyrotechnic cartridge (9) controls tank
opening and allows passage of the gaseous mixture through an outlet orifice (7). Electric power supply
is performed by means of a connector (10).
The tank has three feet (12) which are used to secure it on three support bar stands (4) using screws
(1). These bar stands are screwed onto the connection casing.
The extinguisher has five plates (2) each giving indications and miscellaneous information pertaining to
its use.
Figure 1 - Extinguisher
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3. Pipes (Figure 2)
Injection of the gaseous mixture takes place inside the engine through an extinguisher connector (7)
held by two lugs (8) secured by two assembly screws of the oil tank casing with the air inlet casing.
Since the extinguisher is placed outside the enclosure, a connector (6) secured by a nut (5) allows
crossing the top cover. The connector and the extinguisher outlet orifice (1) are fitted with angle
connections (2) and (4) for a connection pipe (3). The extinguisher connector (7) is screwed onto
connector (6).
Figure 2 – Extinguishing pipes
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4. Storage
A. Extinguisher
The extinguisher tank fitted with its discharge head and it protection plugs will be stored in a room
protected from humidity and at an ambient temperature lower than + 30°C.
B. Cartridge
The electro-pyrotechnic cartridge will be stored separately in an individual packing, in a room with
sufficient safety conditions, according to the rules pertaining to class "C" explosives.
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FIRE EXTINGUISHING
A. Check attachment of tank.
B. Check connection of power supply connector.
C. Check condition of piping attachment.
D. Check locking by lockwire.
E. Check that the pressure indicated by the pressure gauge actually corresponds to that marked on
the pressure temperature correction table at the considered temperature.
2. Removal – installation of extinguisher (Figure 201)
A. Purpose
- Removal of connection casing on which it is attached.

- Replacement after operation.
- Periodic maintenance.
B. Periodicity
- Weighing of complete extinguisher every six months.

- Replacement of cartridge every three years (non-reconditionable).
- Return to factory for overhaul and re-test of extinguisher every five years.
C. Means required
(1) Possible spares
MM IPC
DESIGNATION
Fig. Item Chapter Fig. Item
201 Extinguisher 26-21 1 10M
201 5 Discharge head 26-21 1 11
201 2 Tank 26-21 1 12
201 6 Cartridge 26-21 1 13M
201 Adjustment shims
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(2) Products
- Lockwire
D. Removal
(1) Removal of cartridge
NOTE: This operation will be performed when the cartridge expiry date is reached.
a) Unlock and disconnect the electrical connector (8).
b) Unlock and unscrew the cartridge (6).
c) Recover the adjustment washers.
d) Discard the cartridge (6).
(2) Extinguisher
a) Unlock and disconnect the electric power connector (8).
b) Unscrew the angle connector (7).
c) Unlock and unscrew the cartridge (6).
NOTE: This operation is not to be carried out if the extinguisher is weighed.
d) Unscrew the three screws (1), recover their washers (10), remove the tank (2).
E. Weighing
It is recommended to weigh the extinguisher every six months. The measured weight must not
differ by more than 20 grams from that indicated on the extinguisher identification plate.
F. Installation
(1) Cartridge
a) Position the cartridge (6), screw it on the discharge head (5) and orient it by means of
adjustment washers according to detail A of figure 201.
b) Tighten to a torque load of 2 ± 0.3 and lock.
c) Connect and lock the electric connector (8).
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(2) Extinguisher
a) Place the tank (2) on the stanchions, position the pressure gauge (4) while orienting it
towards the right side of the engine, install screws (1) fitted with their washers (10) and
tighten.
b) Check:
- That the discharge head (5) is in the position indicated by detail A. Otherwise loosen
nut (9) and orient the head (5). Tighten nut (9) to a torque load of 8 daN.m. and lock.
- That the blanking plug (3) is present.
c) Install cartridge (6) as indicated in 2. F.1)
d) Connect the electric connector (8) and lock.
Figure 201- Removal-installation of extinguisher
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STANDARD PRACTICES
TABLE OF CONTENTS
Designation Chapter/Section Page Number
- General instructions 70-00-01 1 to 3
Assembly
- General 70-10-00 1
- Hardware 70-10-01 1 to 3
- Tightening torque 70-10-02 1 to 6
- Locking of assemblies 70-10-03 1 to 6
Standard Assembly
- General 70-20-00 1
- O-rings 70-20-01 1 to 4
- Assembly of clamps 70-20-02 1
- Assembly of pipes 70-20-03 1 to 3
- Assembly of standard connectors 70-20-04 1 to 8
Inspection – Touch ups
- Miscellaneous inspection
and touch ups 70-30-01 1 to 3

1991
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PERIODICITIES

70 1 Sept. 1991 70-20-00 1 May 1981
2 Sept. 1995
70-20-01 1 Sept. 1991
70-00-01 1 May 1981 2 Sept. 1991
2 Sept. 1995 3 Sept. 1991
3 Sept. 1991 4 Sept. 1991
70-10-00 1 May 1981 70-20-02 1 May 1981
70-10-01 1 May 1981 70-20-03 1 May 1981

2 May 1981 2 May 1981
3 Dec. 1983 3 Sept. 1991
70-10-02 1 May 1981 70-20-04 1 May 1981

2 May 1981 2 May 1981
3 Sept. 1991 3 Dec. 1983
4 May 1981 4 Dec. 1983
5 Sept. 1991 5 May 1981
6 May 1981 6 May 1981
7 May 1981
70-10-03 1 Sept. 1991 8 May 1981
2 May 1981
3 Dec. 1983 70-30-01 1 May 1981
4 Sept. 1991 2 May 1981
5 Dec. 1983 3 May 1981
6 May 1981

1995
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STANDARD PRATICES
GENERAL
When applying instructions described in this manual concerning disassembled engine maintenance
and repair by replacement, the following precautions and standard practices must be observed.
1. Precautionay measures
Scrupulous cleanliness, correct utilization of appropriate tools and constant attention to detail are the
basic conditions to be observed at each step of maintenance or repair operation.
Each time a component or accessory is removed, apparent openings and disconnected pipe
connections must be blanked off immediately with appropriate covers, blanking plugs, etc. to avoid
ingress of foreign matter. Whenever a cover is not provided for, use rubber or plastic plugs.
For tightening and loosening of twelve point head nuts or screws, only use the appropriate quality
wrenches.
2. Disassembly
When removing a component or disassembling engine parts, the following precautions must be
observed.
A. Consumables
All parts which cannot be re-used such as synthetic rubber, O-rings, flat seals, brake pads, etc.
must be discarded immediately after removal so that there is no risk of mixing them with new
parts and thus to avoid their re-use.
B. Identification before removal
As long as the maintenance technician does not have enough experience on this engine, small
parts will have to be labelled or notes made during disassembly so that each part is identified with
certainty and correctly during assembly.
C. Separation of components
When components are difficult to separate due to adhesion between two faces of a seal or due to
presence of a centering pin, lightly tap on the periphery of the component with a rubber mallet to
unstick the components. In no case should a sharp edge object be inserted to unstick a
component. Use an extractor if mentioned except if unsticking takes places easily.
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3. Cleaning
Most of the components can be cleaned with white spirit (possibly pressurized) or with an appropriate
solvent and a lintless rag then dried using dry compressed air (preferentially hot).
CAUTION: PARTS MADE OF TITANIUM ALLOY MUST NOT BE CLEANED WITH

TRICHLORETHYLENE. USE WHITE SPIRIT OR ARDRON 552 OR
SIMILAR PRODUCT OR ACETONE OR METHYLETHYLCETONE OR
PETROL F. SINCE THESE SOLVENTS ARE HIGHLY FLAMMABLE,
TAKE THE REQUIRED PRECAUTIONS.
4. Inspection
All components must be carefully examined before installation. Also examine the parts adjacent to
these components for damage and possible traces of friction. The component inspection instructions
are given in the corresponding chapters.
5. Repair
External engine surfaces protected by an anti-corrosion coating must be touched up if the coating is
scratched or scaled (see chapter 70-30-01).
No repair or adjustment of an engine component or accessory is allowed by the user. If there is an

anomaly on a component, it should be replaced or possibly returned to factory for repair.
6. Assembly
During assembly and installation of engine components, refer to the following information:
A. Check of locking torque
(see chapter 70-10-02).
B. Use of screws
C. Anti-corrosion treatment
New or repaired engine equipment items are delivered treated against corrosion.
When an equipment item is removed from the engine, and if it is not to be installed nor
disassembled for reconditioning before a week and must remain in shop or in transit for more
than seven days, it must be stored or protected against corrosion.
Details concerning storage are given in chapter 71-00-05.
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D. Splined drives
WARNING: DO NOT BREATHE ENGINE OIL VAPORS. AVOID SKIN CONTACT

WITH ENGINE OIL. WORK IN A WELL-VENTILATED AREA. OIL IS
TOXIC. IT CAN BE ABSORBED BY THE SKIN AND PENETRATE
IN THE HUMAN BODY. PROTECT HANDS WITH SYNTHETIC
RUBBER GLOVES AND THE FACE WITH A SCREEN OR
GOGGLES.
When installing splined drives on the engine, the drive and the component must be lubricated with
the engine oil except other instructions are given.
These drives must never be assembled dry.
E. Tightness seaIs
(See chapter 70-20-01)
F. Pipes
(See chapter 70-20-03).
G. Installation of clamps
H. Locking
I. Connectors
7. Inspection after intervention
At the end of all maintenance or repair work, make sure that all parts are correctly tightened and that
there is no rag or tool around the engine. In particular, examine the interior of the air inlet.

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ASSEMBLY
GENERAL
Since the engine is built from assembling unit elements, great care taken while assembling will
preserve the engine from a greater number of operating anomalies due to incorrect assembly.
The main assembly techniques are grouped together in this chapter. It is recommended to refer to
these techniques before intervening on the engine.
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ASSEMBLY
HARDWARE
1. General
A major part of assembly is carried out by hardware (screws, nuts, bolts). Incorrect use of these parts
often results in operating anomalies of the engine. It is therefore mandatory to follow certain
elementary measures which guarantee use of these hardware items.
2. General precautions
If assembly is carried out using bolts, and if accessibility so allows, it is preferred to tighten the nuts.
Tightening of adjustment bolts must mandatorily be carried out by nuts.
If flanges are of the multiple attachment type, progressively tighten the connection parts in increasing
tightening torque (see chapter 70-10-02 para 3 D).
During assembly, make sure that the contact faces are clean and free of foreign matter or particles.
Particularly ensure that ordinary screws are not assembled on hot parts in place of high temperature
machined screws made of stainless steel or nickel alloy. The only way of identifying these, is by
referring to the code stamped on the screw head.
3. Length of screws
When components or equipment items are secured using screws and self-locking thread insert
screws, it happens that screws with the same diameter and same pitch may have different lengths.
It is therefore very important that replacement screws be of the same length as those removed. Too
long or too short screws can cause damage, poor attachment or a leak between contact faces.
It is therefore mandatory to use screws having the same reference as those provided by the
manufacturer.
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4. High temperature screws
Screws are divided up as follows:
A. Silver-plated stainless steel screws for use at temperatures between 230 °C and 700 °C used on
casings have their head stamped with code letters "material CM" and figure 7 corresponding to
the "temperature 700°" code. These letters correspond to the last two figures 25 of the
TURBOMECA standard code number (example 9824zzxx25).
B. Cadmium-plated passivated steel screws for use up to 230 °C have their head stamped with code
letters "material BC" corresponding to the last two figures 14 (example 9820zzxx14).
Another letter L or F etc. corresponding to the supplier code can also be found on the screw
head.
NOTE:
1) The first four figures correspond to classification of screws in the TURBOMECA standard:
E.g. 9801 or 9806 hexagonal head screw

9820 or 9824 12-teeth head screw
2) ZZ Screw diameter in millimeters
3) XX Length under head in millimeters
E.g No. 9824051225 corresponds to

a 12-teeth screw (9824)
with 5 mm diameter (05)
with 12 mm length (12)
for use up to 700 °C (25)
Figure 1 – 12-teeth head screws
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5. Removal of assembly hardware of hot parts
To facilitate removal of assembly hardware, a coat of anti-seize compound must be applied to all nuts
and screws assembled on hot parts.
A. Using a brush or a syringe, use TRANSYL anti-seize compound (or equivalent) to impregnate all
assembly screws, nuts or bolts located in the hot part of the engine.
B. Let the product act for 15 to 20 minutes. If the hardware resists, repeat the operation and let the
anti-seize compound to act for a longer time.
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ASSEMBLY
TIGHTENING TORQUE
1. General
When assembling engine parts, certain assembly screws, nuts or bolts must be tightened with a
tightening torque defined by the engine manufacturer as a function of the type of parts to be
assembled and the dimension of threads.
The applicable tightening torques are given in the tightening torque table below or during maintenance
operations.
2. Tightening of assembly components using a torque wrench
A. Purpose
Tensioning of connecting elements, screws, studs, nuts by applying a tightening torque by means
of a torque wrench is an essential condition to avoid dispersion of assembly stresses. In this
respect, certain elements can be overloaded resulting in a risk of prohibitive lengthening or
insufficiently loaded which can result in loosening.
B. Use of a release type torque wrench
(1) Place the cursor index on the desired torque value.
(2) Mount the special end piece corresponding to the nut to be tightened.
(3) By holding the wrench as shown in figure 1, tighten the nut until release of the wrench.
Figure 1 – Use of torque wrench
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(4) When approaching tightening, ensure that:
- the located nuts and screws screw in without abnormal resistance,

- self-locking nuts and screws installed in locking coil thread inserts offer no abnormal
resistance during screwing in.
CAUTION: IF THE WRENCH IS HELD AS SHOWN IN FIGURE 2, THE TIGHTENING

TORQUE OF THE NUT OR SCREW WILL BE LESS THAN THE
TORQUE VALUE SHOWN BY THE CURSOR INDEX.
Figure 2 – Incorrect use of a torque wrench
C. Inspection of torque wrench
The torque wrench must be periodically inspected on a standard spring gauge observing correct
utilization.
3. Application procedure of tightening torques
A. Lubrication
Thread efficiency depends on the type of lubricant. Products used must comply with the following
requirements:
- they should not be corrosive,

- if possible, they should be soluble in machine oil and be eliminated during operation,
- they must be easily procurable by all assembly workshops.
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The lubricants to be used are defined in the following table:
Item Use Lubricant
Vaseline
Bearing locking nut
AIR 3565
- cast iron,
Graphite vaseline
Threaded studs and sockets - steel,
AIR 4247
- light alloys.
Routine hardware Engine oil
- argenté Engine oil

Hardware for hot parts
- non argentée Graphite vaseline
If engine oil is used as lubricant :

WITH ENGINE OIL. WORK IN A WELL-VENTILATED AREA. OIL IS
GOGGLES.
B. Tightening torque of 3.5 daN.m. and more
Any bolting requiring a tightening torque equal to or greater than 3.5 daN.m. must undergo
preliminary tightening to ensure that threads do not stick and approach bearing faces before
applying the final tightening torque.
Proceed as follows:
(1) Lubricate the threads, the bearing faces and the washers.
(2) Tighten until half the indicated torque is reached.
(3) Loosen then tighten until the indicated torque is reached.
C. Pin type cup point locks
Nuts locked by pin type cup point locks must be tightened in two steps as indicated below in order
to straighten the cup point.
(1) Lubricate the threads.
(2) Tighten the nut to the indicated torque value.
(3) Loosen then tighten the nut to the indicated torque value.
When a locking device is used such as cup point lock, lock plate, pin, etc., it is tolerated,
unless otherwise stated, to exceed the recommended tightening torque to approach as close
as possible the locking point.

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D. Tightening order
In certain cases when tightening effort is too high, do not successively tighten the nuts or the sets
of adjacent screws, but respect the following order:
(1) On circular tightening flanges, lightly tighten a pair of diametrically opposite nuts or screws.
Proceed progressively in the same manner around the flange until the bearing faces come
into contact.
Then apply the indicated tightening torque values in the same order.
(2) On the half-casing attaching flange, use the same method
First tighten the nut or screw located in the center, then progressively and alternately tighten
from the center towards the ends.
Figure 3 – Tightening order
4. Definition of locking and tightening torques
A. Locking torque for hardware with self-locking device
This is the torque which is opposed to rotation of the located element without axial stress in the
screw.
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TABLE 1
Locking torques (daN.m.) of self-locking devices
Rated
3 4 5 6 7 8 10 12 14 16
diameter
Maximum
0.075 0.16 0.2 0.32 0.46 0.6 0.95 1.5 2.2 3.3
torque
Minimum
0.01 0.015 0.025 0.035 0.05 0.065 0.12 0.18 0.26 0.37
torque
B. Effective tightening torque
This is the torque required to cause a given axial stress in a screw.
TABLE 2
Effective tightening torque (daN.m)
Rated
3 4 5 6 7 8 10 12 14 16
diameter
Effective
0.065 0.18 0.37 0.62 1.10 1.70 3.10 5.60 9.20 13.50
torque
C. Apparent tightening torque
This is the sum of locking torque and effective tightening torque practical value to be set on
torque wrenches for attachments comprising a self-locking system.
For non self-locking systems, the tightening torque to be set on the torque wrench is equal to the
effective tightening torque (Table 2).
TABLE 3
Apparent tightening torques (daN.m.)
Rated
3 4 5 6 7 8 10 12 14 16
diameter
Apparent
0.100 0.27 0.48 0.8 1.35 2.03 3.63 6.44 10.43 15.33
torque
NOTE: The torque values in Tables 2 and 3 correspond to utilization of machine oil as lubricant.

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5. Assembling non-conventional attachments
After disassembling a part or an assembly, the technician must systematically check the locking torque
of all the self-locking devices. This torque must comply with the values given in Table 1.
The minimum locking torque is checked when unscrewing with the bearing face of the screw or nut not
bearing on the tightening surface.
In practice, for a screw or nut with a diameter ≤ 5 mm, the locking torque will be considered as correct
if the screw or nut can no longer be unscrewed by hand.
Then, during assembly, the technician will set the following on the torque wrench:
- in the presence of a self-locking device on attaching elements, the apparent tightening torque given
in Table 3, as a function of the screw diameter,
- in the absence of a self-locking device on the attaching element, the effective tightening torque
given in Table 2 as a function of the screw diameter.
6. Assembly conditions for normal attachments
If possible screwing in operations must be carried out at ambient temperature, the threads and bearing
faces of screws and nuts are coated with engine oil (unless otherwise stated in the text).
For self-locking systems, in all cases, the screw must protrude the nut or the thread insert by at least
1.5 to 2 pitches (chamfer included). As far as possible, visually check this condition.
However, in no case, should the apparent tightening torque be exceeded to make the screw correctly
protrude.
In no case, should the locking torque be modified by means such as distortion of locking device or
enlarging the tapping.
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ASSEMBLY
LOCKING OF ASSEMBLIES
1. General
This sub-section describes the different locking modes used for immobilizing threaded assemblies.
2. Locking by self-locking nuts with internal packing (Figure 1)
Comply with the apparent tightening torque (70-10-02, § 4).

After tightening, the screw must protrude the nut by one thread minimum not including the terminal
chamfer of the screw.
Figure 1 – Locking by self-locking nut
3. Locking by lockwire (Figures 2 - 3 - 4)
A. General (Figure 2)
Certain types of locking for nuts, screw head connectors, etc. are carried out using lockwire when
these elements are provided with a hole for wire passage.
The lockwire used is of stainless steel. It must always be perfectly tensioned between elements to
be locked and the attaching points and the tension to be applied must resist loosening.
Figure 2 - Locking by lockwire

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The wire ends must be twisted together over approximately 10 mm including a minimum of four
turns and then folded down along one of the elements to be locked.
After installation, the wire must not show any anomalies, markings or cracks.
The wire must be replaced after each disassembly.
B. Locking modes (Figures 3 et 4)
Two locking modes using lockwire are authorized.
(1) Locking by double wire performed as shown in Figure 3.
Figure 3 - Locking by double wire
(2) Locking by single wire when the screws are close together or arranged in closed geometric
figures as shown in figure 4.
Figure 4 - Locking by single wire
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(3) Locking by lock plates
The nut lock made of plate is a piece of metal cut out and placed instead of a washer under a
screw head or a nut when assembling. Lugs anchor the nut or the screw head to the part to
be tightened by resisting to their rotation.
After tightening to the prescribed nut torque, fold down the lugs on the nut irrespective of the
position of the flats. For this operation, use a pair of smooth and round nose pliers.
If accessibility does not allow use of pliers, in this case, exclusively use a special tool (locking
tool and drift).
CAUTION: DO NOT MATE THE FOLD TO PREVENT FORMING A SHARP ANGLE

AND AVOID START OF TEARING. THESE LOCKS MUST NEVER BE
RE-USED.
a) Utilization on right edge or curved edge (Figure 5)
Anchor by folding down
Figure 5 Anchoring by folding down
b) Utilization on ribs (Figure 6)
The lugs are placed on either side of the rib.
Figure 6 - Utilization on ribs
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c) Utilization through a locking hole (Figure 7)
The unused lug can be cut.
Figure 7 - Utilization of a locking hole
d) Utilization of locking tool and drift (Figure 8)
Insert a metal foil plate to avoid marking the part, raise the two nut lugs one after the
other either on one face or on two faces and apply them against the nut using a light
alloy drift.
Figure 8 - Utilization of locking tool and drift

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4. Locking by split pin (Figure 9)
This locking system applies to two hexagonal head notch nuts.
Before inserting the pin in the notches, make sure that the nuts are perfectly aligned in the stud hole.
The pin head must be engaged in the notch.
CAUTION: AS DISASSEMBLY PROGRESSES CAREFULLY, RECOVER THE PINS

AND DISCARD THEM. MAKE SURE THAT NO PIECE PENETRATES
THE ENGINE, AN ACCESSORY OR A DUCT.
Figure 9 - Locking by split pin
Selecting a pin as a function of the screw
Screw diameter (mm) Pin diameter (mm) Pin length (mm)
4 and 5 1 12
6 1.5 15
7 and 8 1.5 20
10 and 12 2 25
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5. Locking by grower washer and tooth washer
Since these washers are not checked on a unit basis, during assembly, ELIMINATE those which show
important anomalies such as:
- distortion, knocks at ends, oxidation.
6. Locking of slotted nuts (Figure 10)
The nut used is a nut lock with tabs. After tightening of the nut to the required torque in order to
straighten the cup point lock, loosen the nut then tighten to required torque then fold down the edge of
the cup point in the nut slots.
Figure 10 - Nut lock with tabs
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STANDARD ASSEMBLY
GENERAL
A large part of the engine components are standard elements supplied externally to TURBOMECA.
They often serve for a specific utilization and assembly. Their routine use in the engine justifies
integrating their handling description in a single chapter in order to avoid repetitions in the manual.
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STANDARD ASSEMBLY
O-RINGS
1. Inspection before assembly
When inspecting O-rings, it is important not to pull them to avoid deformation. This mainly applies
to O-rings with large diameters.
During assembly, check that the rubber parts do not show:
- permanent deformation flats,

- visual signs of a surface which has softened, then hardened,
- blisters cracks, scaling, when the rubber is sagging.
Ensure absence of moulding, only a slight protruding bead (very uniform) is acceptable.
CAUTION: - AFTER EACH REMOVAL OF AN ELEMENT, SYSTEMATICALLY

DISCARD THE O-RING.
- FOR MAGNETIC PLUGS WHICH NEED TO BE DISASSEMBLED

SEVERAL TIMES BETWEEN EACH PERIODIC INSPECTION
OPERATION, THE O-RINGS CAN BE RE-USED AFTER CHECKING
THEIR CORRECT CONDITION. CHECK STORAGE VALIDITY
BEFORE USING A NEW O-RING (refer to para 4).
2. Positioning O-ring using seal shank
Never run the O-ring on threads or sharp edges (see detail Figure 1). Use a seal shank by proceeding
as follows:
Figure 1 – Prohibited installation of an O-ring

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A. Ensure that the seal housing is free of traces of shock and burr; edges must not be sharp.
B. Lubricate the seal and the seal shank with vaseline AIR 3565.
C. Place the seal on the seal shank.
D. Place the seal shank fitted with the O-ring on the threads or sharp edges of the part located
upstream of the groove for which the seal is intended.
E. Carefully slide the O-ring over the seal shank until it falls in the groove intended for it.
F. Withdraw the seal shank.
G. Ensure that the O-ring is correctly installed without twist, well in place in its housing and free of
cuts and tearing.
Figure 2 - Installing an O-ring
3. Positioning o-ring without seal shank
A. Clean the seal housing.
B. Coat the seal and the cylindrical portion where it slides with appropriate lubricant.
C. Slide the seal into its housing by deforming it as little as possible and avoiding twisting the tore.
D. Ensure that the seal is correctly assembled, that the core is not twisted, and that no tearing or cut
occurred during assembly.

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4. Shelf-storage time of O-rings supplied as spares
A. Storage conditions
The rings are delivered in sealed and opaque bags. Awaiting their use, the seals must remain in
their bags and stored under the following conditions:
- Temperature between 10 and 20° C.

- Out of direct sunlight or out of strong artificial light.
- Relative humidity between 45 and 70%.
- Out of aggressive vapors (solvents). Ozone is prohibited therefore, outside a room in which
the following operate, mercury vapor lamps, spark generators, a high voltage electric circuit.
B. Identification
The bags carry various indications according to the manufacturer.
(1) Manufacturer name Order number Number of rings Batch number Mixture number -
Inspection stamp.
(2) The TURBOMECA part number of the ring on the PART or P/N line
Examples: - Part 9794132203.

- P/N 9682001801.
(3) The ring material identified by a group of four characters (two figures one letter one figure)
Examples: 21A7 or 50D7 or 61D6 or 64C8, etc.
This material identification group is located either at the end of the MATERIAL Iine or at the
beginning of the QUALITY line or alone on the QUALITY line.
Examples: - MATERIAL 7DF710/64C8.

- QUALITY 64C880VO13A.
- QUALITY 64C8.
(4) The manufacturing date or CURE DATE identified by a group of four characters (one figure
the letter T two figures):
- the first figure indicates trimester 1 or 2 or 3 or 4,

- the letter T means Trimester,
- the two figures indicate the year,
Examples: - CURE DATE 2T87 (2nd trimester 1987)

- MANUFACTURING DATE 4T85 (4th trimester 1985).

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C. Determination of shelf storage time
The material and manufacturing date indicated on the bag enable determination of the storage
limit date by means of the following table.
Material/storage time relation table
Material Life span Maximum shelf storage time authorized before

Quality group assembly from manufacturing date
20A
20B
21A
II 6 years
21B
23B
24B
31B
32A
III 8 years
41B
42B
50D
51A
52D
IV 10 years
53D
61D
63D
60
62A V 15 years
64C
Examples:
1 ring QUALITY 21A (life span group II)
- CURE DATE 2T87 was manufactured during the 2nd trimester of 1987 and must enter into
service before the 2nd trimester of 1993.
- 1 ring QUALITY 64C (life span group V) MANUFACTURING DATE 1T83 must enter into
service before the 1st trimester of 1998.

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STANDARD ASSEMBLY
ASSEMBLY OF CLAMPS
1. General
The assembly flanges and clamp must be clean and in good condition. During assembly, the
accessory must not be supported by drive shaft splines to avoid any damage; the centering stud of the
accessory must be engaged in the milling of the flange before installing the clamp. The nut and spacer
of the clamp must be placed in such a way as to have easy access to the nut while being placed as far
as possible from the pipes and adjacent connectors.
2. Assembly
Assembly of the clamp and its tightening must be performed as follows:
A. Lubricate the flanges of the equipment and the bearing faces of the clamp with clean engine oil.
B. Ensure correct position of the seal and flanges and install the loosened clamp on the flanges.
C. Apply the clamp against the flanges and tighten to 70% of torque provided.
D. Using a rubber mallet, tap on the circumference of the clamp (when possible) to ensure equal
distribution of the stress.
E. Tighten the nut to the provided torque.
F. Loosen then tighten the nut to the provided torque twice without modifying the position of the
clamp.
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STANDARD ASSEMBLY
ASSEMBLY OF PIPES
1. General
Connection of engine pipes is carried out using standardized connectors.
2. Inspection
A. Cleaning
Perfect cleaning of the pipe enables better inspection.
(1) Clean the pipe system using solvent.
(2) Dry using dry compressed air to avoid any contamination of the system.
B. Inspection of rigid pipes
(1) Check the general condition of the pipes for deformation, absence of cracks or traces of
friction either with equipment items or with other pipes.
(2) Main search for traces of external corrosion and possibly internal corrosion.
(3) Ensure that the pipes are not marked by attaching clamps or by supports. Check that the
locking devices are correct.
(4) Make sure of the good condition of identification rings (color of system concerned, fluid type
and direction of flow).
C. General aspect examination of flexible pipes
CAUTION: A FLEXIBLE PIPE MUST NEVER BE FLANGED FOR TRACTION,

TENSION OR COMPRESSION. IT SHOULD NOT BE BROKEN BY
CONTINUOUS OR INTERMITTENT PRESSING.
(1) The central part of the flexible pipe must show a bottoming flexibility when slightly sollicited.
(2) Check condition of pipes at locations where they are susceptible to rub against a fixed
element.
(3) If the pipe shows traces of wear, it should be replaced.
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3. Connectors eguipping pipes (Figure 1)
A. Description and operation
These connectors comprise a sleeve (2) and a nut (3) located on a standard tube (1) whose end
flares at 37°.
Flaring of the pipe is applied against the connection cone which equips the engine accessory or
the engine on which the pipe is to be connected, and the nut is screwed onto this connector.
Tightening of the nut enables through a sleeve, tightness of the pipe and connector.
Figure 1 – AN connector
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B. Nut tightening torques
Correct operation of this type of connector depends on mandatory compliance of tightening

torques to be applied to the connector nut.
A torque which is too low can result in loosening of the connector during operation; a torque
which is too high can cause sagging of the male conical bearing with risks of leakage or rupture of
the connector.
These tightening torques are given by the following table. They must mandatorily be applied using
a torque wrench whose precision degree must be in relation with the measurement to be
performed.
A measurement is valid only if the divisions on the torque wrench are below the tolerance range
of the installation torque of connectors.
Threads are lubricated with vaseline.
Tightening torque Tightening torque

Pipe diameter Pipe diameter
(daN.m) (daN.m)
4 1.1
6 1.8 16 5.6
8 1.8 20 10.5
10 2.5 25 12
12 3.9
14 4.7

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STANDARD ASSEMBLY
ASSEMBLY OF STANDARD CONNECTORS
1. General
Pipes are connected together or on accessories using standardized connectors.
2. Inspection of connectors
A. Cleaning
Perfect cleaning of the pipe enables better inspection.
(1) Clean the pipe system using solvent.
(2) Dry using dry compressed air to avoid any contamination of the system.
B. Inspection
(1) Check cleanliness of the different elements forming the connector.
(2) Examine the ring section of the connector male end pieces and make sure that they do not
show signs of circular scratching or longitudinal scoring.
(3) Similarly examine the ring section of female end pieces.
(4) Check that threads do not show signs of burrs or crushing.
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3. Direct location connector
A. Nipple (Figure 1)
This connector is used for connecting a pipe to an accessory or the engine.
Figure 1 – Nipple
B. Elbow (Figure 2)
When a pipe cannot be run perpendicularly to the surface of the accessory or the engine, this
connector replaces the fitting. Its particularity is to allow orientation in the position which facilitates
pipe connection.
Installation of this connector is carried out as follows:
(1) Installation of connector
With the counternut (1) screwed in completely on the connector, manually screw (without
tightening) the connector in its location.
(2) Orientation
If required, turn the connector in the unscrewing direction until the desired orientation is
obtained, unscrewing will always be less than one turn.
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(3) Tightening
Tighten the counternut (1) while maintaining the orientation of the connector.
Figure 2 – Elbow
C. Other connectors
There are other connectors of the same type which are not used in this engine.
4. Link or union connector (Figure 3)
The use of direct location connectors is limited insofar as they require a certain amount of space for
installation which is not always available.
The link connector equipped with a branch connector palliates this drawback. Moreover they adapt to
accessories and particularly to solenoid valves installed on connectors.
In this respect, these connectors enable the link without connector or accessory operation. They also
enable orientation of the considered connector or accessory.
They are used as follows:
A. Installation of link connector:
Screw in and tighten the link connector on the accessory inserting appropriate seals, tighten by
body (2).
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B. Installation of branch connector
Install the branch connector on the link connector or install the accessory by offering the link
connector on the branch connector, carry out the required orientation.
C. Tightening
Screw in nut (1) of the link connector on the branch connector, tighten.
Figure 3 - Link or union connector
5. Branch connector (Figure 4)
A. Elbow
This connector has the same function as the direct location elbow.
B. T-connector
This connector is used to connect two pipes on an accessory or three pipes together.
C. Cross connector
This connector is used in the engine for fuel distribution to the solenoid valves which differentiate
the three fuel systems.
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Figure 4 – Branch connector
6. Secondary branch connector
A. Elbow (Figure 5)
This connector has the same function as the elbows already defined above but is used on a
branch connection. It is also orientable.
Figure 5 – Secondary branch connector
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MAINTENANCE MANUAL
B. Other connectors
There are other secondary branch connectors to be screwed onto branch connectors. These are
not used in this engine.
7. Special connector
A. Bulkhead crossing (Figure 6)
This connector is used for crossing a bulkhead with one pipe. It is held in a drilling in the bulkhead
by a nut and receives a pipe at each end.
Figure 6 – Bulkhead crossing
B. Plug (Figure 7)
Figure 7 - Plug
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C. Tapped sleeve
When the accessory is fitted with a threaded end, this connector is used to adapt standard
connectors.
Figure 8 – Tapped sleeve
8. Tightness
Tightness of located connectors is ensured either by a brass or light alloy seal or by an O-ring held in a
retaining ring.
On each removal operation, the seals and O-rings must systematically be replaced.
9. Assembly
A. Lightly coat threads bearing faces of the connector and seals with vaseline.
B. Screw in and install the connector as described above for each of them.
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C. Tighten by applying the respective tightening torques:
Tighten torque of
Tightening torque of
Pipe diameter connector on connector
located connector (daN.m.)
(daN.m)
6 2 1.4 –1.6
8 2.5 1.9 – 2.1
10 3.5 2.8 – 3.1
12 5 4 – 4.5
14 7.5 6–7
16 7.5 6–7
20 12 10 – 11
25 15 13 – 14
Tightening must be sufficient to ensure correct tightness and must not be excessive. This would
be useless and could destroy the seals and contact surfaces. This is why tightening torques must
mandatorily be applied with a torque wrench whose precision degree must be in relation with the
measurement to be performed.
A measurement is valid only if the divisions on the torque wrench are below the tolerance range of
the installation torque of connectors.
10. Inspection of assembly
During routine maintenance inspections, check connector tightness and if required, carefully tighten the
faulty connector by applying the special instructions of each connector.
If the leak still remains, remove the faulty connector and replace the seals.
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INSPECTION – TOUCH UPS
MISCELLANEOUS INSPECTION AND TOUCH UPS
1. General
During routine maintenance operations on the engine and accessories, inspection is reduced to minor
operations. In certain cases, the technician must consult the appropriate chapter for complementary
operations and for acceptance tolerances.
2. Inspection methods
A. Visual inspection
Visual inspection detect the following anomalies:
- Rupture.
- Cracks, scaling, shocks, scratches.
- Distortion, wear, caulking.
- Traces of overheating (poor lubrication), abnormal overheating.
- Corrosion, dirt, erosion.
NOTE: Do not confuse oil coloration and burns with traces of overheating. In the first
case, oil coloration is uniform, accompanied sometimes with a deposit whereas
in the second case, there is formation of different color schemes.
B. Dye penetration method
To locate cracks, this method will be preferred.
Three different liquids are used:
- a solvent (appropriate) for cleaning the part to be examined of all impurities (grease oil),
- a red product which penetrates the cracks and porosities,
- a volatile liquid which leaves a fine film of white powder.
This powder attracts the red penetrating product out and exactly situates the crack location.
(1) Carefully degrease the part to be tested with solvent.
(2) As far as possible, place the part to be checked horizontal.
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(3) Using a fine brush apply the red penetrating liquid and coat the part to be tested with a fine
film.
(4) Vibrate the part by lightly tapping with a wooden mallet so that the liquid penetrates inside
possible cracks.
(5) After about 20 minutes, carefully wipe off with a dry and lint free cloth.
NOTE: The remaining traces of the red product may be removed from the surface
using a cloth very lightly soaked in solvent.
(6) Using a brush, apply the white developer liquid. Leave to dry.
(7) Interpretation:
- a brightly colored Iine indicates a crack,

- a dotted line indicates fatigue cracks,
- spaced points indicate metal porousness.
(8) After the check, carefully clean the part with solvent.
3. Checks to be performed on installed or removed assemblies
A. Cast parts
Check the surfaces surrounding studs; no crack is tolerated. Check the flanges, bearing faces
and sealing plane.
B. Gears
Make sure that the gear teeth are not pitted or scaled and that they do not show signs of irregular
wear.
Check the smoothness of pinion bearings and ensure that they show no signs of excessive
friction or overheating.
C. Welded parts
Make sure that there is no crack, visual inspection with magnifying glass (5 to 10x magnification)
or according to the dye penetrant method.
D. Various supports
- Check external and internal condition. Make sure there are no signs of contact with the
engine equipment items.
- Check condition of edges and connection seals.
- Check attaching elements (latches, screws, nuts).
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4. Minor repairs
A. Traces of erosion, corrosion, friction, scratches
Attenuate these traces using a stone and/or by lightly polishing by hand.
5. Protection of repaired parts
A. Clean the parts with white spirit and dry with dry compressed air.
B. If paint is not available, a temporary protection can be applied by spraying a fine layer of water
repellent product however avoiding plastic parts.
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TURBO-GENERATOR UNIT
TABLE OF CONTENTS
General
- Turbo-generator unit 71-00-01 1 to 3/4

- Installation 71-00-02 1 to 5
Maintenance operations 201 to 204

- Fuels lubricants
and miscellaneous products 71-00-03 1 to 3
- Storage and destorage 71-00-05 201 to 219
Enclosure
- Package 71-10-01 1 to 8
Structure
- Attachments and lifting 71-20-01 1 to 2
Catch locks
- Structure assembly 71-40-01 1
Electrical equipment
- Electrical harnesses 71-50-01 1 to 5
Maintenance operations 201 and 202
Drains
- Equipment 71-70-01 1
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PERIODICITIES

71 1 Sept. 1995 71-10-01 1 May 1981
2 Sept. 1995 2 May 1981
3 Sept. 1995
71-00-01 1 May 1981 4 May 1981
2 May 1981 5 May 1981
3-4 May 1981 6 May 1981
7 May 1981
71-00-02 1 Dec 1983 8 May 1981
2 May 1981
3-4 May 1981 201 May 1981
5 Sept. 1995 202 May 1981
203 May 1981
201 Sept. 1991 204 Sept. 1995
202 Sept. 1991 205 May 1981
203 Sept. 1991
204 Sept. 1991 71-20-01 1 May 1981
2 May 1981
71-00-03 1 June 1994
2 Sept. 1995 71-40-01 1 May 1981
3 June 1994
71-50-01 1 Sept. 1991
71-00-05 201 Sept. 1991 2 Sept. 1991
202 Sept. 1995 3 Sept. 1991
203 Sept. 1991 4 Sept. 1991
204 Sept. 1991 5 Sept. 1991
205 Sept. 1991
206 Sept. 1991 201 May 1981
207 Sept. 1995 202 May 1981
208 Sept. 1991
209 Sept. 1991 71-70-01 1 May 1981
210 Sept. 1991
211 Sept. 1991
212 Sept. 1995
213 Sept. 1995
214 Sept. 1991
215 Sept. 1991
216 Sept. 1991
217 Sept. 1991
218 Sept. 1995
219 Sept. 1991
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GENERAL
1. General
The turbo-generator unit installed on board Eridan class Minehunters comprises a gas turbine
ASTAZOU IV M1 and an alternator AVAB 315 L26.
The gas turbine and alternator are interconnected with intermediate shaft and thus form a compact
unit.
2. Characteristics of ASTAZOU IV M1 turboshaft engine
The ASTAZOU IV M1 turboshaft engine supplies power of 320 kW and rotates at a speed of
1,800 rpm. Drive side rotation direction is clockwise when looking at the engine from the front. It
comprises all the parts required for its startup and control of the turbine speed during all the operation.
This speed varies according to the load (proportional regulation).
It has an independent lubrication system. The oil tank and lubrication pumps are built into the engine.
Only the oil cooler is installed on the alternator.
Its fuel system includes all the parts required for completely automatic operation:
- The combustion chamber is ignited by two igniters and two fuel nozzles.
- Acceleration is carried out by progressive injection of fuel controlled by the startup unit.
- A control unit sets and maintains the desired rotation speed within a certain limit range. This unit
also includes a pump for supplying the pressure required for the fuel.
The following set of elements monitors the engine:
- three fire detectors,

- a fire extinguisher,
- a low oil pressure switch,
- an oil temperature probe,
- a high oil temperature thermal switch,
- an exhaust gas temperature pyrometric harness,
- an engine rotation speed magnetic sensor.
The engine is protected by a package. Cooling air which flows around the engine is supplied by the
alternator.
The engine is held in a balanced position on the alternator by means of a circular flange which
reduces attachment of the turbo-generator unit to attachment of the alternator only.
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3. Characteristics of turbo-generator unit
The general characteristics of the turbo-generator unit are as follows:
- Height 1,440 mm.

- Width 810 mm.
- Length 3,316 mm.
- Total weight 2,070 kg in running order.
The power unit supplies the alternator terminals with nominal power of 250 kW under 450 V at a
frequency of 60 Hz and a cos phi of 0.8.
The operating temperature range of the turbo-generator unit is 15 °C to + 35 °C at atmospheric

pressures between 900 and 1,050 mbars. These climatic condition variations obviously influence the
maximum power available.
The turbo-generator unit is secured to the ship by the four support feet of the alternator.
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Figure 1 – Overall dimensions of turbo-generator unit
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GENERAL
INSTALLATION
1. Fuel supply
The engine must be supplied with fuel (not containing water) at a pressure regulated between 0.2 and
0.9 bar, but without a pulsation greater than ± 0.05 bar. The required flow rate is 200 litres/hour with
filtration of 5 microns.
Fuel inlet into the group is by means of a connector (12) located on the front cover of the enclosure.
NOTE: See chapter 71-00-03 for fuel specifications.
2. Oil supply
The oil to be used must comply with NATO standard 148 or 150 depending on the ambient operating
temperatures. The oils complying with these standards are synthetic oils which can be mixed together.
The total volume of oil in the engine system is approximately 20 litres. The tank is filled from the top
through a plug (16) and drained at the bottom through two blanking plugs (8).
3. Electric power supply
The unit is powered by 24 V DC electric current.
The starter absorbs a peak current of 700 to 900 A and an average current of 400 A for 40 seconds
(startup time). Its power supply is via a connector (1).
For the other engine accessories, a total current capacity of approximately 10 A should be provided.
The power supply system for these accessories must be such that, at the first moment of their setting
into service, the voltage at their terminals be greater than 18 V. This voltage should never be below
16 V at any operating moment. Two connectors are used for their connection, one (4) for control
accessories (solenoid valves, servovalve, etc.) and the other (7) for checking accessories (detectors,
probes, etc.). Connection of the fire extinguisher and cooling air louver actuating device is ensured by
two dedicated connectors, respectively (3) and (10).
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4. Combustion air supply
The turbine absorbs a combustion air flow rate of 2.55 kg/s. This air must be as clean as possible.
Content in air of Na C1 must not exceed 0.01 ppm (naval specification).
The combustion air enters from the top, through a rectangular opening (13) equipped with a flange
(14) on which an air guide duct is secured. This duct must not exert stress on the flange. The load loss
will be as low as possible since this is related to engine power loss.
5. Cooling air supply
3
The alternator fan sucks in air through the oil cooler at a rate of approximately 1 m /s. This air ensures
cooling of the alternator engine oil and of the engine under the enclosure. In fact, once crossing the
alternator, the air enters the enclosure through sleeve (9) and exits through the nozzle (5). The exhaust
pipe in the venturi is used as an ejector to evacuate air into the smoke stack.
6. Gas exhaust
A circular flange (6) behind the enclosure is used to connect a gas exhaust stack. This stack and the
muffler (if any) must ensure a gas flow rate of 3.85 kg/s at a temperature of 500 °C. The gases are
essentially composed of hydrocarbon combustion gas with four times more air in excess.
The system must have a minimum load loss in order not to cause power loss on the engine and disturb
alternator cooling.
7. Drain
Oil or fuel is rejected from the engine through a general drain orifice (11) fitted with a connector for pipe
connection.
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Figure 1 – Boundaries of turbo-generator unit
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ASTAZOU IV M1
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8. Sampling
A regular analysis of the engine oil enables detecting and forestalling most of the engine anomalies.
Oil is sampled through a quick-connect STAUBLI connector (2).
9. Cleaning and protection
From the point of view of materials, the turboshaft engine is specially designed for use in marine
atmosphere.
However the compressors can clog which can affect their aerodynamic characteristics and
consequently performance of the turboshaft engine.
Thus to clean and forestall possible corrosion, it is necessary to ensure washing and protect the air
duct (see method in 72-20-02 pages 201 to 206).
In this respect, the turboshaft engine has a spraying manifold used to spray the required products.
Powering of this manifold is by means of connector 15 (Figure 1).

1995
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TURBOMECA
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1. Removal-installation of turboshaft engine
A. Purpose
- End of TBO.
- Anomalies requiring return to a repair workshop.
- Removal of connection casing or torque limiter.
B. Means required
(1) Spares
201 5 O-ring 72-11 1 21
(2) Tools
- Hoisting plate No. 8813193000.

- Multipurpose frame No. 8811640000.
(3) Products
- Mastinox compound 6856 K/D 150/2.

- Grease AIR 4247.
C. Preliminary steps (Figure 201)
For the following operations:

WITH ENGINE OIL. WORK IN A WELL VENTILATED AREA. OIL IS
GOGGLES.
(1) Remove side and bottom covers (1) (see 71-10-01 pages 201 to 204).
(2) Drain turboshaft engine oil through the two drain plugs located one at the bottom of the tank
and the other at the bottom of the connection casing (Refer to 72-80-02 pages 201 to 203).
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D. Removal (See Figure 201)
(1) Disconnect electric connectors (3) from the front panel.
(2) Disconnect washing and inhibition product injection pipe (front panel).
(3) Disconnect the fuel supply pipe (2) (front panel).
(4) Disconnect oil cooler inlet and outlet pipes (7) (front panel).
(5) Disconnect extinguisher outlet pipe (8).
Figure 201 – Removal-installation of turboshaft engine
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(6) Install the lifting tool on the air inlet and secure it by means of twelve attachment screws.
(7) Sling and switch on the lifting beam.
(8) Loosen and remove 24 attachment screws nuts, and washers (6) of the turboshaft engine on
the connection casing rear flange (4).
(9) Remove the turboshaft engine and place it on a frame.
(10) Discard O-ring (5).
E. Installation (See Figure 201)
(1) Clean attachment flange bearing surfaces with solvent. Dry with compressed air.
(2) Place an O-ring (5) on the connection casing flange (4).
(3) Apply Mastinox compound to the attachment flange bearing surfaces.
(4) Sling and lift the turboshaft engine using the lifting beam.
(5) Position the turboshaft engine taking care to correct meshing of the shaft (if necessary,
manually rotate the turbine).
(6) Place the 24 attachment screws, nuts and washers (6). Tighten to a torque load of 3.5
daN.m.
(7) Remove the lifting tool.
(8) Connect the oil cooler inlet and outlet pipes (7) (front panel).
(9) Connect the extinguisher outlet pipe (8).
(10) Connect the fuel supply pipe (2).
(11) Connect the washing and inhibition product injection pipe.
(12) Connect the electrical connectors (3) on the front panel.
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F. Return to operating conditions

GOGGLES.
(1) Install inner cover (See 71-10-01 pages 201 to 205).
(2) Fill the oil tank.
(3) Carry out a general ground run check.
(4) If necessary, top up the oil tank..
(5) Install the side covers (See 71-10-01 pages 201 to 205).
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FUELS, LUBRICANTS AND MISCELLANEOUS PRODUCTS
1. General
The ingredients required for operation and maintenance of the turboshaft engine are grouped into
identical utilization categories:
- Fuels.
- Lubricants (oils greases).
- Miscellaneous products.
2. Fuels
The fuel used in the turboshaft engine complies with specification STM 7120 GASOIL Marine 20
(NATO F-76).
3. Lubricants
A. Greases
Brands or specifications
Type Use
France USA GB
Pure mineral AIR 3565 U.V.P. 236 DF.ST-91-38-PX7 Shrinking of sealols

vaseline and bearings.
Hardware on cold
parts. Installation of O-
rings.
Graphite mineral AIR 4247 MIL-T 5544 DF-ST-8080

Hardware on hot parts.
Vaseline
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MAINTENANCE MANUAL
B. Oils
The oil used for turboshaft engine lubrication is a synthetic oil type ESTER doped for anti-wear
and anti-oxidation and complying with NATO standard 0-150 (AIR 3514).
NATO 0-148 oil can also be used.
Specification
NATO Examples of oil which can be
Type of oil
symbol used
France USA UK
CASTROL 325
NORMAL CASTROL 3 C
MIL-L
USE 0.148 - - ESSO TURBO OIL 2389
7808
MOBIL OIL AVREX 256
Synthetic fluid TURBONYCOIL 160
3 to 3.5 cSt at
98.9 °C ELF JET SYNTHETIC OIL 15
0.150 AIR 3514 - -
TURBONYCOIL 13B
AEROSHELL 560 (a)

CASTROL 5000 (a)
ELF TURBOJET II
MIL-L See
0.156 - ESSO TURBO OIL 2380 (a)
OTHER OILS 23699 Note
MOBIL JET OIL II (a)
Synthetic MOBIL JET OIL 254
average TORBONYCOIL 600 (a)
5 cSt to
98.9 °C AEROSHELL 555
DERD
0.160 - - ESSO TURBO OIL 25
2497
CASTROL 599
- - - - TURBONYCOIL 525-2A
NOTE: The MOD generated standard DERD 2499 which groups only the oils marked (a).
WARNING: THE OIL PRESCRIBED FOR NORMAL USE IS SYNTHETIC FLUID

0.150 SPECIFIED UNDER THE HEADING NORMAL USE. THE OILS
MENTIONED UNDER "OTHER OILS" CAN BE USED BUT ARE NOT
RECOMMENDED. THEIR USE WILL BE LIMITED TO AMBIENT
TEMPERATURES GREATER THAN 15 °C.
NOTE: 1) The oil brands are listed in alphabetical order.
2) Specifications are understood as being at their latest amendment.
3) Utilization of oils of specifications and brands different than those mentioned

must be subject to agreement by TURBOMECA.
4) When changing oils with different specifications and brands, rinse the system
according to the instructions of the Maintenance Manual in 72-80-02 pages
201 to 205.

1995
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4. Miscellaneous products
Type Brands or specifications Use
Commercial white spirit External cleaning

Solvents
(DCEA 202 B) Soaking of removed parts
Removal of hardware from hot

Penetrating oil Transyl
or oxidated parts
Products for miscellaneous of ARDROX 6342 (9PR4L)

treatments ARDROX 396/1 E.28.1 or
ARDROX 396/1 E14 or Washing and protection air path
ROCKET WD 40 and turboshaft engine
ISOPROPYLALCOOL or compressors
METHANOL
Demineralized water
ARDROX 185/4 Cleaning of injectors
HYMOLAR SQ 32 M and SQ 32
Sealing compound L Seal bearing surfaces
MASTINOX 6856 K/D
Desiccant bags De humidifies air in containers

Storage products
TEEPOL type detergent Detection of leaks in containers
Aerosol for cleaning electrical

Contact 60 or 80
contacts
LOCTITE 242 (normal thread

Special products Hardware locking
lock)
W3 ARDROX 970 P17

Crack detection
9D3/9DHA

1991
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MAINTENANCE MANUAL
STORAGE - DESTORAGE
1. General
Shutting down an engine beyond a certain time period requires its protection against corrosive agents
(atmospheric or climatic).
The most efficient protection consists on one hand of washing and protecting the gas path by spraying
an appropriate product, and on the other hand, in enclosing the engine inside a sealed metal container
with insertion of desiccant bags.
If a container is not available, a waterproof and vapor-proof cover can be used but safety is of a lesser
degree and can require more or less frequent renewal of desiccant bags.
In cases where this is not possible (case of turboshaft engines installed on Eridan class Minehunters),
protection is only partially ensured.
During operation, two storage types can be considered:
A. Short-Term storage (ST)
Storage is said to be of short term when the engine is protected for a maximum period of one
month. It includes all internal and external storage operations provided for but conditioning in
packing is not carried out.
B. Long-Term storage (LT)
Storage is said to be of long term when the engine can be protected against external agents for a
period of more than one month. It includes all internal and external storage operations provided
and requires conditioning of the engine in packing. The engine delivery contractual conditions
provide for packing in a metal container.
For long-term shelf storage time, see paragraph 5.
NOTE: Due to particularly unfavorable climatic conditions of the storage location, it may be
necessary to increase the frequency of inspections and storage operation renewal: it
is the user's experience in this domain that can supply the required indications.
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2. Short-term storage (ST)
A. Turboshaft engines installed on board Eridan class Minehunters
(1) Duration
This should not exceed 3 months.
(2) Operations to be performed

GOGGLES.
a) Protection of air path
See chapter 72-20-02 pages 201 to 205.
b) Protection of lubricated areas
See chapter 72-80-01 page 206.
c) Protection of fuel system
d) Blanking of orifices
Install blanking plugs on air inlet and exhaust provided for this purpose.
NOTE: To ensure protection of the engines on board the Eridan class

Minehunters, it is necessary to be able to carry out at least one weekly
ventilation operation per engine.
The 24 V DC electric power source can obviously be different from the on
board source.
(3) Return to service
a) Remove the blanking plugs and check for absence of foreign bodies inside the air inlet
and inlet casing.
b) Wash the air path as per chapter 72-20-02.
c) Return the engine to operating condition.
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B. Turboshaft engines to be removed from Eridan class Minehunters
(1) Duration
Maximum one month.
(2) Operations to be performed
WARNING: DO NOT BREATHE ENGINE OIL VAPORS. AVOID SKIN

CONTACT WITH ENGINE OIL. WORK IN A WELL
VENTILATED AREA. OIL IS TOXIC. IT CAN BE ABSORBED
BY THE SKIN AND PENETRATE IN THE HUMAN BODY.
PROTECT HANDS WITH SYNTHETIC RUBBER GLOVES AND
THE FACE WITH A SCREEN OR GOGGLES.
a) Perform operations 2. A. 2) a to 2. A. 2) c).
b) Remove the engine according to chapter 71-00-02 pages 201 to 203.
c) Install blanking plugs (air inlet - exhaust – reduction gearbox power drive - oil and fuel
orifices).
d) Wrap it in a plastic cover and do not close to avoid condensation.
e) Place the engine in a dry location protected from shocks.
(3) Return to service:
WARNING: DO NOT BREATHE ENGINE OIL VAPORS. AVOID SKIN

CONTACT WITH ENGINE OIL. WORK IN A WELL
VENTILATED AREA. OIL IS TOXIC. IT CAN BE ABSORBED
BY THE SKIN AND PENETRATE IN THE HUMAN BODY.
PROTECT HANDS WITH SYNTHETIC RUBBER GLOVES AND
THE FACE WITH A SCREEN OR GOGGLES.
a) Perform installation and reconditioning of engine according to chapter 71-00-02 pages

201, 203 and 204.
b) Wash the air path before returning the engine to service.
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3. Long-term storage (LT)
Long-term storage is carried out in two ways:
- In a plastic cover.
- In a metal container.
A. In a plastic cover (Figure 201)
NOTE: As far as possible, after storage in a cover, the engine will be placed in a case to
protect it against possible shocks.
(1) Procedure

GOGGLES.
NOTE: Operations 2. A. 2) a) (protection of air path) and 2. A. 2) b) (protection of

lubricated areas) are not necessary since storage takes place in a controlled
atmosphere.
a) Protection of fuel system
b) Removal of engine
Operation 2. B. 2) b) and c).
c) Lay the polyethylene cover (1) with a thickness of 20 to 30/100th on the storage
support (3). Pierce holes at the locations corresponding to passage of attachment bolts.
d) Place the support frame (4) after inserting rubber washers for passage of bolts on either
side of the cover (1). Tighten the bolts taking care that the cover does not fold under the
washers.
e) Place the engine (2) on the frame (4) then padding on the sharp edges of the engine.
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f) Above and below the engine, arrange 20 UF desiccant bags with the color indicator
visible from the exterior.
CAUTION: THE DESICCANT BAGS MUST BE REMOVED FROM THEIR

PACKING AT THE MOMENT OF PLACING THEM ON THE
ENGINE.
NOTE: UF= French unit = 600 cm3 of dehydrating product

1 UF = 16 American units as per standard MIL D 3464.
g) Solder the cover however leaving a small hole. In this hole, insert a suction tube and
create partial vacuum inside the cover.
h) Finish soldering so that the cover is sealed.
i) Place the engine log book at the location provided for it in the case.
Otherwise secure it to the cover using adhesive tape.
j) Close the case, if necessary.
k) On the case or on the cover, affix a label indicating the name and engine serial number,
the date of storage; this label will also contain periodic inspection markings.
l) Place the equipment sheltered from humidity.
Figure 201 - Placing in plastic cover
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(2) Periodic inspections
a) Every month, open the case and check the color of the humidity indicators.
b) If the color is blue (safe), close the case after noting the inspection date on the storage
sheet.
c) If the color is pink (unsafe), open the cover:
- If there are no traces of corrosion, replace the desiccant bags with new ones, close
the cover and create vacuum.
- If there are slight traces of corrosion, remove them, redo the external protection,
replace desiccant bags, close the cover and create vacuum.
- If the traces of corrosion are too important, inform TURBOMECA, replace the
desiccant bags, close the cover, create vacuum and send the engine to the repair
workshop or to the factory.
- On the storage sheet, note the inspection date and possible remarks.
(3) Shelf storage time
See paragraph 5.
(4) Return to service
No special operation.
See chapter 71-00-02 pages 201, 203 and 204.
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B. In container (Figure 202)
(1) Preparation of turboshaft engine
Prepare the engine as per the indications detailed in 2. B. 2) a) and b).
(2) Opening the container
a) Open the document door (1) which gives access to the control unit (11) and ensure that
there is no pressure in the container.
b) Remove the 26 bolts (2) attaching the cover (1) then remove cover (1).
Figure 202 - Views of various elements of container
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(3) Disassembly of cover guides
a) For the front guide (12) located towards the desiccant bag basket (9), remove the 2
pins, extract the shaft and remove the guide.
b) For the rear guide (5), carry out the same operations.
(4) Preparation of turboshaft engine support frame
a) On both front supports (4), remove the two pins, extract the spindles and washers.
b) On the rear support (7), remove the pin, extract the spindle and washer.
NOTE: Loosen the three HM 14-70 screws attaching rear support (7) to frame (8)
to enable adjustment during installation of the turboshaft engine.
Otherwise, remove the rear support and secure it below the turboshaft
engine before its installation on the frame.
(5) Handling and installation of turboshaft engine
a) Disassemble the two side panels of the turboshaft engine to enable installing the rear
attachment.
b) Secure the lifting system to the turboshaft engine and carefully lift the assembly.
c) Present the turboshaft engine on the support frame (8) with the front oriented towards the
bag basket (9).
d) Slowly lower the turboshaft engine until the two front attachment lugs and the rear
attachment lug come in the slot of each attachment of the frame.
e) On both front supports (4), install spindles, washers and pins.
f) On the rear support (7), install the spindle, the washer and the pin; adjust the position
and tighten the 3 HM 14-70 screws to a torque load of 5 daN.m.
g) Assemble the two turboshaft engine side panels.
(6) Installation of air suction cover
a) Install the cover on its support frame (13), with the inlet sleeve oriented towards the rear
of the container.
b) Install the 4 cover attachment screws in the holes of the support and tighten.
(7) Installation of cover guides
a) Re-install the front and rear guides (5) and (12) on the resting squares.
b) Install the shafts in the holes and install the pins.
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(8) Closing the container and conditioning
a) Install desiccant bags in the basket (9).
b) Quantity 23 French units (600-g bags)
• according to RT 22 - IA Chap IX
• formula IV NU = 5 V
with V = 4.412 M3 total volume of container
• therefore 5 x 4.412 = 23 French units approx.
c) Ensure that the tightness seal (3) is in place.
d) Install the cover (1) positioned by centering pin.
e) Install the 26 attachment bolts (2).
f) Tighten progressively to obtain maximum tightness.
g) Open the document door (10) which gives access to the control unit (11).
h) Ensure for the presence of the safety valve and all control accessories to be ready for
sweeping and pressurizing the container.
Figure 202 - View of various elements of container
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(9) Sweeping the container (Figure 203)
a) Open the document door (1) giving access to the control unit (3) inside which are
located the valve (2), pressure gauge (4) and safety valve (6).
b) Unscrew the plugs on the 2 hood connectors.
c) Connect the pressurized dry air inlet pipe to the INPUT hood connector equipped with
the sweeping pipe (7).
d) Connect the drain pipe (8) fitted with the humidity indicator (9) to the other OUTPUT
hood connector.
e) Sweep the interior of the container with air from a dehydrating unit (10) until the relative
humidity level of the air is less than 20.
f) Disconnect the pipes (7) and (8) and install blanking plugs fitted with seals in perfect
condition on the hood connectors.
g) Remove plug (5) and install a humidity indicator.
Figure 203 - Sweeping of container
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(10) Pressurizing the container (Figure 204)
a) On inflating valve (2), connect a pipe connected to the source of nitrogen or dehydrated
air (10).
b) Pressurize the container:
- Relative pressure of 250 hPa under standard and temperature conditions.

- Reading on pressure gauge (4) located inside the unit (4) and checked by calibrated
pressure gauge (9) installed on the air or nitrogen inlet pipe.
- The air source (10) must comprise a detector (11) adjusted approximately to 1 bar
relative pressure.
c) Disconnect the pipe and install the plug on valve (2).
For different external conditions, refer to the graph on page 214.
WARNING: PAY GREAT CARE AS TO THE CONDITION OF THE

VALVE AND PRESSURE GAUGE (ACCIDENTS POSSIBLE
BY EXCESS PRESSURE).
Figure 204 - Pressurizing the container
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(11) Final check
a) One hour later, check the pressure in the container:
- If no loss is noticed, the container is ready.

- On the contrary, if a pressure drop is observed, search for the leak(s) using soapy
water (Teepol type detergent) applied on the contour of the seal with a brush.
- Tighten the seal if the leak is confirmed and re-pressurize the container.
b) Install lead seals on the screws or centering studs of the cover.
c) Place the engine log book in a polyethylene bag and place it in the document door (1)
giving access to the control unit (3). Also place the storage sheet with containerizing
date and type of storage.
d) On the container, note the type, order number, and serial number of the engine.
NOTE: Insofar as possible, the container must be placed sheltered from the sun or
any other source of thermal radiation.
(12) Periodic inspections
a) During the week which follows containerizing, open the document door (1) to read the
pressure on the pressure gauge (4). If the pressure has dropped, search for a leak
using soapy water or SHERLOCK C G product and repair. Then re-inflate the container
with nitrogen or if not available, with dry air through valve (2).
b) Every six months, check the color of the humidity indicator (2) and the pressure on the
pressure gauge (4).
1- If the pressure is less than 100 hPa and if the humidity indicator is blue, no operation
is to be performed. Fill in the storage sheet.
2- If the pressure is less than 100 hPa and if the humidity indicator is blue, pressurize
the container (operation 2. B. 10). Fill in the storage sheet.
3- If the humidity indicator is pink whatever the pressure, make the pressure to drop
through valve (2) and open the container. Check the engine condition, replace the
humidity indicator.
- If there are no traces of corrosion, replace the desiccant bags, close the container
and condition it.
- If there are slight traces of corrosion, eliminate them and carry out the complete
storage operation.
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- If the corrosion is important, inform TURBOMECA, close the container, condition

it and send the engine for repair. Fill in the storage sheet.
CAUTION: IF TRANSPORT IS BY AIRCRAFT, DEFLATE THE

CONTAINER IF AIR TRANSPORT IS ABOVE 16,000 FEET
(5,000 METERS).
(13) Shelf storage time
See para 5 (page 218).
(14) Opening the container and removing turboshaft engine
a) Deflation of container:
- Open the document door giving access to the control unit.

- Remove the valve blanking plug and open the latter to balance the external and
internal pressures.
- Slowly evacuate the dehydrated air or nitrogen.
- Unscrew the plugs on hood connectors to leave the container in free air.
b) Opening the container and removing turboshaft engine:
- Perform the operations described in paragraphs 3. B. 2) to 3. B. 8) of this chapter in

reverse order.
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(15) Graph indicating inflation pressure as a function of external conditions
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Figure 205 - Dimension of container
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4. Storage - packing of equipment
Except special specifications are indicated, the equipment removed from the engine, awaiting or
intended to be returned to the factory or to the repair workshop must undergo long-term or short-term
storage operations.
A. Long-term storage
Shelf storage time: refer to paragraph 5.
This storage includes internal and external storage operations described below and packing in
tight polyester container.
(1) Internal storage
a) Purely electric equipment items do not undergo any internal storage operation.
b) Oil systems must be drained.
c) Fuel systems must be filled with fuel used for engine operation and blanked.
d) For air systems, and if their configuration so allows, spray a water repellent product on
them in compliance with standard AIR 3634 (NATO C-634).
(2) External storage
a) Blank systems using appropriate blanking plugs as well as connectors.
b) On all the external surface, spray a water repellent product in compliance with standard
AIR 3634.
(3) Packing
a) Carefully wrap the equipment using grease proof paper.
b) Place one or several desiccant bags against the wrapping.
c) Insert the assembly in a polyethylene cover with a just sufficient size; compress the
cover (or create vacuum using a pump) to drive out the maximum of air; tightly solder
the opening.
d) Place the assembly in a tight polyester container with wedging materials and
appropriate wadding. Place the identification sheet and the equipment sheet or follower
sheet, if required.
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NOTE: Several small size equipment items can be placed in the same container
provided each item is conditioned individually.
For larger assemblies made of sheet steel, with a simple structure, the
container can be a wooden or carton case.
e) After closing the container, affix another identification label on it.
(4) Long-term storage inspection
Regularly check the color of the desiccant indicator, see paragraph 5. If the color turns,
repeat the equipment storage operations.
B. Short-term storage
This type of packing must be used only exceptionally. It protects equipment only for a maximum
duration of one month.
The same internal and external storage procedure as for long-term storage is used but the tight
container and desiccant bags are not necessary.
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5. Shelf storage time as a function of applied procedure
A. Engine removed from Eridan class Minehunters – Non electronic equipment
Interval
Total - Brief reminder of storage method
Basic total between two
cumulable Type of detailed in Maintenance Manual.
shelf storage humidity
shelf storage storage
time indicator
time - Possible checks to be performed.
inspections
4 years 6 months Long-term In metal container pressurized after

internal and external storage of
equipment
- pressure check and humidity
indicator (*) after one week then
every 6 months
After 4 years of storage, return the
equipment to the factory
4 years 1 year 1 month Long-term In wooden case or plastic container

equipment in tight polyethylene
cover 20/100 mm thick transparent
or aluminized
- internal and external storage of

equipment
- relative vacuum + desiccant bags
- monthly inspection of humidity
indicators (*)
- storage renewal every year
- after a maximum of 4 years of
storage, return of equipment to
factory
1 month Short-term - Outside case or container internal

and external storage protected
from dust and humidity
If one or several O-rings in bags are delivered apart from equipment items or modules to enable
their installation on the engine, see chapter 70-20-01 concerning the storage limit for these
O-rings.
(*) If the color of the humidity indicator changes, inspect the parts and if oxidation is present,
inform TURBOMECA.
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B. Engine installed on an Eridan class Minehunters
Immobilization Type of storage to Actions

period provided for be performed
Maximum 7 days None - Air inlet and exhaust pipe blanking plugs
in place, airframe closed.
Maximum 3 months None - Ventilation of 20 s every week.
- If engine can be rotated, air inlet and

or exhaust pipe blanking plugs in place,
cover closed, weekly inspection.
Greater than 3 Short-term - Remove the engine from the Minehunter

months carry or Long-term and carry out long-term or short-term
storage as a function of the
immobilization period provided for.
C. Storage guaranteed
Application of storage guarantee as defined in the TURBOMECA general guarantee conditions

(article 2) is strictly conditioned by observance of the storage and inspection procedures
described in this document.
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ENCLOSURE
PACKAGE
1. General (Figure 1)
The ASTAZOU IV M1 turboshaft engine is enclosed in a locally tight package which on one hand
protects the engine and its accessories and on the other enables cold air flow from front to rear to
externally cool the engine and its accessories.
This package comprises a front frame (1) a rear frame (4) through which engine exhaust gases and
cooling air are evacuated and two side covers (2), a top cover (3) and a bottom cover (5) fitted with a
sleeve (6) through which cooling air produced by the alternator is introduced.
Figure 1 - Package
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2. Front frame (Figure 2)
The front frame is formed by two sheet steel half-frames (8) assembled around the oil tank casing.
This assembly enables obtaining a frame whose four sides are folded down and which comprises a
central opening with a shape matching that of the oil tank casing.
The top part is assembled by tightening the half-frames between a gusset (9) and a support plate (7).
The bottom part is assembled by a lap seal (3).
Tightness between the frame and the oil tank is obtained by means of a seal (4) maintained by
nineteen lugs (12) secured to the frame by nineteen screws (1). Four of these screws are also used to
maintain plate (7) and lap seal (3). The gusset is fitted with crimped tapped sleeves receiving eight
screws (6) for assembly of the top part. The lap seal is maintained by two other screws (2) which are
screwed into two crimped sleeves in the frame.
The frame is fitted with two catch locks (15) which enable attachment of the bottom cover. They are
attached on the frame by four screws (14).
The frame is maintained on the support assembly (11) of the engine by ten screws (13) and nuts (10)
and by two upper screws (14) attaching the catch locks. The frame is drilled with several holes (5)
used for passage and attachment of engine equipment items (connectors, pipes, etc. ).
Figure 2 – Front frame
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3. Rear frame (Figure 3)
The rear frame comprises a rectangular sheet steel plate (8) equipped with point-welded
reinforcements and accessories.
The folded down edges are reinforced by two rigidity gussets (11) on each side, and the angles are
equipped with support plates (1).
A flange (7) bordered with a forged rib is added to attach an evacuation duct for engine exhaust gas
evacuation outside the compartment and the ship.
At its center, the frame has a large circular opening through which the engine exhaust pipe passes.
The rear frame is fitted with two catch locks (9) which enable attachment of the bottom cover. The
catch locks are secured by four screws (10).
The rear frame is supported on the engine support assembly (3) by ten screws (4) and nuts (2) and by
two top screws (10) for attaching the catch locks. Certain indications concerning the engine are
engraved on a plate (6) attached to the frame by four rivets (5).
Figure 3 – Rear frame
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4. Side covers (Figure 4)
Each side cover comprises a rectangular sheet steel plate (3) welded to a frame (4) formed by four
angle irons assembled by welding. The folded down edges of the plate are welded together to the
angles. Two external cross beams (10) are added on the top and bottom sides and two other internal
cross beams (2) vertical inside the frame. They are maintained by welding and ensure rigidity of the
cover.
The side covers are positioned on the engine support assembly (12) by their frame (4) and are held in
place by wing screws (11) screwed on threaded rods (13) welded to the support assembly. The
screws fitted with large welded washers bear on the flaps (6) maintained on the covers by screws (5)
and nuts (8). These flaps are retractable enabling fast removal and installation of the covers without
completely unscrewing the wing screws (see MAINTENANCE chapter).
Tightness is ensured by four rubber bands (1) bonded on the bottom sides of the plate between the
folded edges and the frame. Handling of the covers is facilitated by two crimped and welded
handles (9). A TURBOMECA sticker (7) is affixed to the center of the covers.
Figure 4 – Side covers
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5. Top cover (Figure 5)
The top cover comprises a sheet steel rectangular plate (5) with its longitudinal edges folded down.
A large rectangular opening allows passage of air required by the engine.
Reinforcements are added on and point-welded under this place to obtain greater rigidity. Four
reinforcements form a frame (9) on the extreme edges of the cover, four others which are intermediate
form a frame (6) around the opening. A plate (4) and another central reinforcement (10) are welded
between the two frames along the longitudinal axis of the cover. A drilling and a lug (3) in the plate
enable attachment of fire extinguishing pipes (see chapter 26-20-01).
The top cover is maintained on the engine support assembly (12) by six wing nuts (7) screwed onto tie
rods (8) in the form of a hook attached in the holes of the support. The nuts fitted with washers bear
on the reinforcement plates (11) welded to the cover.
Tightness between the cover and the support is ensured by six rubber bands (2) bonded on the
external frame and at the opening by four other bands (1) bonded to the internal frame. The latter bear
on four support plates (14) maintained by eight screws (13) between the flange of the air inlet opening
of the air inlet casing (16) and four tapped bars (15) in which the screws are screwed.
Figure 5 – Top cover
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6. Bottom cover (Figure 6)
The bottom cover comprises a support frame formed by four beams (2) on which two side panels (6),
a cover base (4) and a front panel (1) are welded. This assembly forms a sort of a corner funnel to
enable cooling air flow towards the engine inside the package. The air enters through a rectangular
opening on the front panel. Four internal nuts and four external lugs (11) frame this opening for
securing the air inlet sleeve. Several reinforcements (8) are added on the side panels.
Engine drain pipes are maintained on the cover by six mounting brackets (7) to be directed towards a
general drain orifice drilled on the front panel. A tapped hole (10) is welded on this orifice.
Each end of the side beams is equipped with a drilled reinforcement (9) by which the engine support
assembly is attached to the cover. Assembly is made by wing screws (15) bearing on catch locks (16)
of the front and rear frames and screwed into shafts (14) placed in the reinforcement drillings. The
shafts are immobilized in movement by the wing screws which are themselves immobilized by two
washers (13) placed on either side of the screws on the shafts in the reinforcements. The screws pivot
with the shafts to enable quick removal-installation of the cover without completely unscrewing them. A
split pin (12) prevents complete unscrewing.
Figure 6 – Bottom cover
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Four rubber bands (3) ensure tightness of the cover. Two lap seals (5) are added on the longitudinal
beams to retain the bands.
7. Sleeve (Figure 7)
The sleeve comprises a duct (1) fitted at the rear with a welded clamp (2) which enables attachment
on the bottom cover (19).
Attachment is by four clamps (4) which bear on lugs (20) of the bottom cover and press on the clamp
between the cover by means of four wing screws (5) located in nuts (18) welded on the cover.
Centering is performed by the duct which penetrates into the cover opening. Tightness is obtained by
four rubber bands (3).
Inside the sleeve, a flap (10) enables closing by rotation in the two bearings (6) of a support shaft (8)
on which it is secured by five screws (16). The bearings fitted with crimped friction sockets are
attached to the duct by eight screws (15). Two flanges (11) reinforce the duct at this point.
Figure 7 - Sleeve
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The left bearing is crossed by a screw (17) which is used for adjusting the transverse position of the
flap by actuating the shaft.
The right bearing is fitted with an electric motor (12) used to move the flap by driving the shaft. It is
maintained on the bearing by four screws (14) and is fitted with an electric connector (13) for
connection to a power source.
The sleeve also comprises two vertical reinforcements (9) at the center of the duct and a seal (7)
bonded on the front.
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PACKAGE
1. Removal-installation of side cover (Figure 201)
A. Purpose
The side covers are removed to access the engine and some of its accessories.
B. Means required
(1) Possible spares
201 8 Rubber width 50 71-11 1 16
201 9 Rubber width 34 71-11 1 17
(2) Products:
- Glue 3M
C. Removal
(1) Unscrew the six wing screws (2) by a few turns until flaps (4) swivel around their shafts, push
them slightly if required.
(2) By pulling on handles (6), disengage the cover (5) and remove it.
Figure 201 – Removal-installation of a side cover
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D. Inspection
(1) Check the condition of the tightness rubber bands, replace them if necessary.
E. Installation
(1) Using the handles (6), place the cover (5) on the engine structure such that the nuts (2)
cross the cover through orifices (1). Centering with respect to the structure is ensured by the
cover frame. Pay attention to cover direction: check with respect to the TURBOMECA logo
(7), moreover the flaps (4) must not blank the nut passage orifices.
(2) Fold down the flaps (4) towards the shafts (3) by sliding them behind nuts (2), completely
unscrew these nuts if necessary to facilitate this operation (unscrewing is limited by two weld
points on the shaft end). While maintaining the flaps in place, screw the nuts without
tightening them until the flaps hold by themselves. Perform this operation flap after flap.
(3) Once the flaps are folded down and maintained, tighten the nuts moderately by hand with
equal effort on each of them (regular crushing of rubber).
CAUTION: NEVER USE A TOOL TO TIGHTEN THE NUTS.
2. Removal-installation of bottom cover (Figure 202)
A. Purpose
The bottom cover is removed to access the engine and some of its accessories.
B. Means required
(1) Spares
(See the table in the preceding paragraph)
(2) Products
- Glue 3M
(1) Remove the side covers.
D. Removal
(1) Unlock and unscrew knurled nut (7), disconnect power supply connector (6) of the sleeve air
flap actuator.
(2) Remove the 4 sleeve (8) attaching clamps on the bottom cover, push the sleeve by a few
centimeters into the ventilation duct.
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(3) Unscrew connector (4) and remove the general drain pipe (5).
(4) Unscrew connectors (1) from drain and vent pipes (2) which lead to the general drain orifice
of the bottom cover passing through the cover mounting brackets. Remove these pipes in
the cover without removing the mounting.
(5) Unscrew the attachment wing screws (11) by a few turns until the cover (3) comes off the
engine structure by 1 or 2 cm.
(6) Raise the cover until it contacts the engine structure, the screws (11) must disengage from
catch locks (9) by pivoting around their axis, assist in pivoting if required by disengaging lock
blade washers (10) and remove the cover.
Figure 202 – Removal-installation of bottom cover
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E. Inspection
(1) Check the condition of the tightness rubber bands, replace them if necessary.
F. Installation
(1) Position the cover under the engine.
(2) Raise the rear of the cover and fit the rear wing screws (11) onto corresponding catch
locks (9), paying attention to washer (10), insert it in the catch blade.
(3) Carry out the same operation with the front of the cover.
(4) Screw in the four wing screws (11) correctly centering the cover on the engine structure,
tighten them moderately by hand exerting equal force on each of them (regular crushing of
rubber bands).
CAUTION: NEVER USE A TOOL TO TIGHTEN THE SCREWS.
(5) Install drain pipes (2), screw in and tighten connectors (1).
(6) Install the general drain pipe (5), screw in and tighten connector (4).
(7) Install sleeve (8) on the bottom cover; install and tighten the 4 attachment clamps.
(8) Connect the electrical connector (6), screw in knurled nut (7), tighten and lock with lock wire.
G. Return to operating condition
(1) Install the side covers.
3. Removal-installation of suction nozzle (Figure 203)
NOTE: Removal of the suction nozzle is to be carried out only on Eridan class Minehunters pre-
mod. M004 of N.L. Marine.
A. Purpose
- Removal of exhaust pipe
B. Means required
(1) Spare
203 4 Seal 71-11 1 4
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(1) Remove exhaust stack section connected to the engine.
D. Removal
(1) Unscrew the fifteen attachment screws (2), recover their washers (3), remove the nozzle (1)
and discard the seal (4).
E. Installation
(1) Install the nozzle (1) on the rear frame (5) inserting a new seal (4). Screw in the fifteen
screws (2) fitted with their washers (3). Tighten.
F. Return to operating condition
(1) Install the exhaust stack.
Figure 203 - Removal-installation of nozzle
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STRUCTURE
ATTACHMENTS AND LIFTING
1. General
The engine frame is an assembly of parts fixed for its use or its transport and lifting parts for handling.
2. Attachment of engine unit
Assembly of the engine with the alternator is performed through the connection casing (see chapter
72-10-01). The engine is maintained balanced by this assembly which enables reducing attachment of
the unit only by the alternator.
3. Transport (Figure 1)
Three supports are used to secure the engine to a transport or storage frame This frame can itself be
secured to a trolley for handling. A support (3) is maintained at the rear by three of the screws (4)
attaching the turbine casing and the two others (2) by six of the screws (1) attaching the oil tank casing
at the front.
Installation of the engine on the transport frame requires removal of the bottom cover.
Figure 1 - Attachments
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4. Lifting
Lifting of the turboshaft engine alone is by means of a slang hooked onto a hoisting plate (1). The plate
is secured on the air inlet of the turboshaft engine by means of 8 screws (2).
Figure 2 – Lifting
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CATCH LOCKS
STRUCTURE ASSEMBLY
1. General
The engine is fitted with a structure assembly for securing the engine enclosure and certain
accessories.
2. Description
The attachment structure of the engine comprises four uprights (1) and four beams (6).
The uprights are maintained on the air inlet casing by eight screws (10). On each end, they are fitted
with welded plates (4). On each of these plates, a shock damper (9) is maintained by four screws (8).
The beams each comprise two welded U-brackets (5) for attaching the shock dampers by screws (7).
At each end, they are fitted with gussets (3) through which the front and rear frames of the packaging
are secured. They each include three threaded rods (11) for securing the side covers.
An accessory support plate (12) is maintained on the right side of the engine by the side uprights and
by two other screws (2) which are screwed into the sockets crimped into the plate.
Figure 1 – Structure assembly
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ELECTRICAL EQUIPMENT
ELECTRICAL HARNESSES
1. General
The electrical equipment of ASTAZOU IV M1 comprises three electrical harnesses each with a distinct
function. Each of these harnesses is fitted with a main connector maintained on the enclosure front
frame and used for quick connection of the electrical system to the control panel.
2. Starting harness (Figure 1)
The starting harness consists of an electric connector (6) from which lead out two electric cables (4)
each terminated by a crimped lug (1) protected by a sleeve (2). Another marked sleeve (3) is used to
identify one of the cables. The connector is fitted with an identification plate (5). This harness supplies
electric power to the starter on which it is connected.
Figure 1 – Starting harness

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MAINTENANCE MANUAL
3. Control harness (Figure 2)
The control harness consists of an electric connector (1) from which lead out ten electric cables (3)
ended by different elements according to their function:
- The two pressure switch power supply cables comprise three electric conductors (14), each
separated at the cable end. These conductors are fitted with connection lugs (13) protected by
sleeves (10).
- The servovalve power supply cable is ended by an electric connector (12) connected to the cable
by a connector (11).
- The solenoid valve power supply cables are equipped with connectors (9) fitted with attachment
clips.
- The microswitch unit power supply cable is equipped with a connector (7) fitted with a cable clamp
(6).
- The high energy unit power supply cables are ended by an electric connector (4).
Each cable is fitted with an identified sleeve (5) to enable identification. Certain cables are held
together by three clamps (8). The connector (1) is fitted with an identification plate (2).

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Figure 2 – Control harness

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4. Monitoring harness (Figure 3)
The monitoring harness consists of an electric connector (6) from which lead out eight electric cables
ended by different elements according to their use:
- The three fire detector power supply cables, the thermocouple unit power supply cable, the probe
power supply cable and thermal switch power supply cable, each comprise two electric conductors
(7) separated at the end of the cables. These conductors are fitted with connection lugs (4)
protected by sleeves (8).
- The thermal probe power supply cable comprises three conductors (2) separated at the end of the
cable. These conductors are terminated by connection clips (1) protected by sleeves.
- The magnetic sensor power supply cable is fitted with an electrical connector (9).
Each cable is fitted with a marked sleeve (3) used for identification.
Connector (6) is fitted with a identification plate (5).
Figure 3 – Monitoring harness

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5. Assembly of harnesses (Figure 4)
The three electrical harnesses are maintained on the engine and together by clamps (1), (11) and
(12). Fixed receptacles (10) on the engine receive some of these clamps.
The main connectors (7) for connecting these harnesses are maintained on the front frame (5) by four
screws (6) and nuts (4). They are arranged on the right hand side, one below the other starting from
the top starting harness (2) followed by the control harness connector (9) and the monitoring harness
connector (8) at the bottom. Each of these connectors receives the power supply cable connector (3)
from the control panel.
Figure 4 – Assembly of harnesses

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MAINTENANCE MANUAL
ELECTRICAL HARNESSES
1. Removal-installation of electrical harnesses
A. Purpose
Replacement in the event of deterioration.
B. Means required
(1) Spares
201 6 Ty-rap clamps (as 71-51 1 15-37-40

required)
201 3 Starting harnesses 71-51 1 1
201 4 Control harnesses 71-51 1 16
201 5 Monitoring harnesses 71-51 1 23
(2) Products
- Lockwire 0.6 mm.
C. Removal (see Figure 201)
(1) Disconnect connectors (1) which connect the on-board circuit.
(2) Remove as required the front panel connectors.
(3) Disconnect the electric connectors supplying the various control and monitoring elements.
CAUTION: MARK THE WIRES IN CASE OF DOUBT.
(4) Cut the plastic clamps all along the harnesses (as per requirements).
(5) Remove the metal clamps at the level of the pyrometric harness (if required).
(6) Carefully extract the electrical harnesses to be replaced.
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D. Installation
(1) Install the harnesses as per the path provided for (see Figure).
(2) Install the front panel connectors.
Figure 201 – Removal-installation of electrical harnesses
(3) Connect the electric connectors supplying the various control and monitoring elements.
(4) Install plastic clamps all along the harnesses at their locations provided for or identified (quantity
on request (AR)).
(5) If necessary, install the metal clamps on the pyrometric harness.
(6) Connect the connectors (1) which connect the on-board circuit.
E. Return to operating condition
(1) Carry out a ground run check.
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DRAINS
EQUIPMENT
1. General
The general drain orifice of the engine bottom cover is fitted with parts which enable connection of
general drain pipe.
Connector (6) of the bottom cover (7) receives another connector (3) enabling connection of the pipe
using an end fitting (2) and a tightening clamp (1). This pipe is used to evacuate liquids rejected by the
engine outside the ship compartment. Tightness is ensured by an O-ring (5) maintained in a retaining
ring (4).
Figure 1 – Drain equipment
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TURBOMECA
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TURBOSHAFT ENGINE
TABLE OF CONTENTS
General
- Engine composition 72-00-00 1 to 4

Trouble shooting 72-00-01
• General 101
• Ventilation 111
• Ignition 121 to 123
• Startup 131 to 134
• Control 141 to 142
• Operation 151 to 152
• Lubrication system anomaly 161 to 163
• Other anomalies 171
Power drive
- General 72-10-00 1
- Connection casing 72-10-01 1 and 2
- Torque limiter 72-10-02 1 and 2
- Reduction gearbox 72-10-03 1 to 7
Air inlet
- General 72-20-00 1
- Air inlet casing 72-20-01 1 to 3
- Spraying manifold 72-20-02 1 to 3
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Compression
- General 72-30-00 1 and 2

- Compressor counter-casing 72-30-01 1 and 2
- Axial compressor 72-30-02 1/2 to 12
- Centrifugal compressor 72-30-03 1 to 9
Combustion
- General 72-40-00 1
- Turbine casing 72-40-01 1 to 5
- Combustion chamber 72-40-02 1 to 6
Turbines
- General 72-50-00 1
- Shielding 72-50-01 1 and 2
- Turbine 72-50-02 1 to 6
- Diffuser bearing 72-50-03 1 to 3
Accessory drive
- General 72-60-00 1
- Pinion system 72-60-01 1 to 4
- Relay box 72-60-02 1 and 2
Lubrication
- General 72-80-00 1
- System operation 72-80-01 1 to 3/4
- Oil tank casing 72-80-02 1 to 3
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- Lubrication unit 72-80-03 1 to 12

- Internal ducts 72-80-04 1 to 7
- Pipes 72-80-05 1 to 6
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TURBOSHAFT ENGINE
72 1 June 1994 72-10-02 1 May 1981

2 Sept. 1991 2 May 1981
3 Sept. 1991
4 Sept. 1995 201 May 1981
5 June 1994 202 Déc. 1983
6 Sept. 1995 203 May 1981
204 Sept. 1995
72-00-00 1 May 1981 205 May 1981
3/4 May 1981
72-10-03 1 May 1981
72-00-01 101 May 1981 2 May 1981
111 May 1981 3 May 1981
121 May 1981 4 May 1981
122 May 1981 5 May 1981
123 May 1981 6 May 1981
131 May 1981 7 Sept. 1991
132 May 1981
133 May 1981 72-20-00 1 Sept. 1991
134 May 1981
141 May 1981 72-20-01 1 May 1981
142 May 1981 2 May 1981
151 Sept. 1995 3
152 May 1981
161 Sept. 1991 72-20-02 1 May 1981
162 Sept. 1991 2 May 1981
163 Sept. 1991 3 May 1981
171 May 1981
201 June 1994
72-10-00 1 May 1981 202 June 1994
203 June 1994
72-10-01 1 May 1981 204 June 1994
2 May 1981 205 Sept. 1995
206 June 1994
201 Sept. 1991
202 Sept. 1991 72-30-00 1 Sept. 1991
203 Sept. 1991 2 May 1981
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72-30-01 1 May 1981 72-40-02 1 May 1981

2 May 1981 2 May 1981
3 May 1981
72-30-02 1/2 Sept. 1991 4 Déc. 1983
3 Sept. 1991 5 Déc. 1983
4 Sept. 1991 6 Sept. 1991
5 Sept. 1991
6 Sept. 1991 72-50-00 1 Sept. 1991
7 Sept. 1991
8 Sept. 1991 72-50-01 1 May 1981
9 Sept. 1991 2 May 1981
10 Sept. 1991
11 Sept. 1991 72-50-02 1 May 1981
12 Sept. 1991 2 May 1981
3 May 1981
72-30-03 1 May 1981 4 May 1981
2 May 1981 5 May 1981
3 May 1981 6 Sept. 1991
4 May 1981
5 May 1981 201 Sept. 1991
6 May 1981 202 Sept. 1991
7 May 1981
8 June 1994 72-50-03 1 Sept. 1991
9 May 1981 2 Sept. 1991
3 Sept. 1991
72-40-00 1 Sept. 1991
201 Sept. 1991
72-40-01 1 May 1981 202 Sept. 1991
2 May 1981 203 Sept. 1991
3 Sept. 1991 204 Sept. 1991
4 May 1981 205 Sept. 1991
5 May 1981
72-60-00 1 May 1981
201 May 1981
202 May 1981
203 May 1981
204 May 1981
Page 5
by the notice appearing on the information page 72 June 1994
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
72-60-01 1 May 1981 72-80-03 1 May 1981

2 May 1981 2 May 1981
3 May 1981 3 May 1981
4 May 1981 4 May 1981
5 May 1981
72-60-02 1 Sept. 1995 6 Sept. 1991
2 Sept. 1995 7 Sept. 1991
8 Sept. 1991
201 Sept. 1995 9 Sept. 1991
202 Sept. 1995 10 Sept. 1991
203 May 1981 11 Sept. 1991
204 May 1981 12 Sept. 1991
72-80-00 1 May 1981 201 Sept. 1991

202 Sept. 1991
72-80-01 1 May 1981 203 Sept. 1991
2 Sept. 1991 204 Sept. 1991
3/4 Sept. 1991 205 Sept. 1991
206 Sept. 1991
201 Sept. 1991 207 Sept. 1991
202 May 1981 208 Sept. 1991
203 May 1981 209 Sept. 1991
204 May 1981 210 Sept. 1991
205 Sept. 1991 211 Sept. 1991
206 Sept. 1991 212 Sept. 1991
213 Sept. 1991
72-80-02 1 May 1981 214 Sept. 1991
2 Déc. 1983 215 Sept. 1991
3 Déc. 1983
72-80-04 1 May 1981
201 Sept. 1991 2 May 1981
202 Sept. 1991 3 May 1981
203 Sept. 1991 4 May 1981
204 Sept. 1991 5 May 1981
205 Sept. 1991 6 May 1981
7 May 1981
72-80-05 1 May 1981

2 May 1981
3 Sept. 1995
4 Sept. 1995
5 Sept. 1991
6 Sept. 1991
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GENERAL
COMPOSITION OF ENGINE
The ASTAZOU IV M1 turboshaft engine basically comprises:
- A compressor with an axial stage (3) followed by a centrifugal stage (4).

- A centrifugal fuel injection annular combustion chamber (5).
- A three-stage axial turbine (6).
- An exhaust diffuser (7).
- A reduction gearbox (2) with accessory drive (9).
- A torque limiter (1).
- An independent lubrication system comprising a lubrication unit (8) and an oil tank casing (10).
2. Operation
The ASTAZOU IV M1 engine is a single shaft turbine or linked turbine. The compressor part and the
expansion turbine part are fit on the same shaft which, through a reduction gearbox and a torque
limiter, drives the receiving machine (alternator).
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Figure 1 – Composition of engine
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MAINTENANCE MANUAL
TROUBLE SHOOTING
ON ASTAZOU IV M1
1. General
In spite of its high technicity, the ASTAZOU IV M1 turboshaft engine can show operating anomalies
due to a fault of one of its constituting elements. Correct maintenance of the engine considerably
reduces the number of possible faults, thus the necessity to correctly follow the periodicity of
maintenance operations. The complexity of its operation which renders easy operation complicates
trouble shooting.
This chapter deals with a set of faults which can occur, analyzes the possible causes and indicates the
appropriate remedial actions to be taken. It does not pretend to list all the faults which can or could
occur but only the most usual failures whose occurrence probability was observed by experience on
the different ranges of turboshaft engines in service. During progressive operation, and the engine's
own experience, this chapter will be arranged and completed later.
Before undertaking trouble shooting operations, first of all, make sure that all checks and operating
instructions have been complied with. No reference has been made concerning omissions or false
manoeuvres such as circuit-breaker not triggered, handle in incorrect position as well as external leaks
or disconnected controls. The faults described here only involve the engine accessories, the control
panel, the alternator, the fuel system assigned to the ship, the air inlet and outlet equipment for
exhaust gases which are external to the engine are assumed to be in good operating condition.
It is reminded that a ventilation operation be performed after each aborted start and after each
intervention on the fuel system.
The text is divided up as follows:
A. Engine operating sequence
(1) Operating anomaly observed
General trouble shooting.
a) Failure:
- Operations to be performed to determine the failure.

- Appropriate remedial action to be applied if the failure is effective.
NOTE: The failures are given in a certain order. It is recommended to keep this
order and to follow it step by step in order to facilitate trouble shooting and
increase the chances of finding the fault.
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VENTILATION
1. Engine does not rotate
A. Faulty starter
- Check starter electric power supply. Remove the starter to check its operation.
- Replace the starter.
B. Relay box fault
- Check starter operation.

- Send the relay box for repair.
C. Faulty starting harness
- Check that starting voltage is present at the harness connector terminals.

- Replace the harness.
D. Faulty starting harness connector
- Check connector wiring.

- Re-wire or replace connector.
2. Engine rotates slowly
A. Lubrication unit failure
- Remove the unit to check that it turns freely.

- Send the unit for repair.
B. Control unit failure
- Remove the unit to check that it turns freely.

C. Relay box failure
- Remove the relay box and check that it turns freely.

- Send the relay box for repair.
D. Engine failure
- Manually rotate the engine through the exhaust diffuser to ensure that there is no friction, hard
points or rubs.
- Send the engine for repair.
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IGNITION
1. Engine does not rotate
See chapter VENTILATION para 1.
2. Engine rotates slowly, ignition time is abnormally high
See chapter VENTILATION para 2.
3. No ignition, no temperature t4 rise, safety system stops engine
A. Fuel general system failure
- At engine exhaust, check for absence of fuel vapors.

- Repair the component of the faulty system.
(1) Fuel filter clogged
- Check filter condition.

- Replace filter.
(2) Fuel pump failure
- Check pump operation by replacing the fuel control unit with a new one.
- Send the fuel control unit for repair.
B. Fuel ignition system failure
- Check the operation of the ignition electrical system as follows: extract the igniters from the
turbine casing without disconnecting them, secure them to the casing with lockwire at a
location where they can be seen by the operator and check for sparks during starting.
- Repair the faulty component of the system if the electric system is in good condition.
(1) Faulty ignition solenoid valve coil
- Check the electric power supply of the coil, check its operation by replacing it with a new
one.
- Discard the faulty coil.
(2) Faulty ignition solenoid valve
- Check coil operation (1).

Check operation of the solenoid valve by replacing it with a new one.
- Discard the faulty solenoid valve.
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(3) Control harness failure
- Check for voltage presence at the terminals of the harness connector corresponding to
the ignition solenoid valve power supply.
(4) Faulty connector

- Re-do wiring or replace connector.
(5) Injectors clogged
- Check by replacing them by new injectors.

- Discard clogged injectors and check fuel filter.
C. Ignition electrical system failure
- Check system operation as indicated in B.

- Repair the faulty component.
(1) Faulty ignition units
- Check for presence of ignition voltage at the power supply terminals of the units, the
control harness.
Check operation of ignition cables (2) and igniters (3).
- Replace the units.
(2) Faulty ignition cables
- Check operation of cables by replacing them with new ones.

- Discard faulty cables.
(3) Faulty igniters
- Check operation of igniters by replacing them with new ones.

- Discard faulty igniters.
(4) Faulty control harness
- Check for presence of ignition voltage at the terminals of the harness connector
corresponding to the ignition unit power supply.
(5) Faulty connector

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D. Failure of temperature t4 measurement assembly
- At engine exhaust, check for presence of hot gases when starting.

- Repair the faulty component.
(1) Pyrometric harness failure
- Check for presence of an output voltage at the connection unit, connection terminals
which must be proportional to the exhaust gas temperature.
- Send the harness for repair.
(2) Faulty monitoring harness
- Check if the output voltage at the connection unit connection terminals is present at the
general connector terminals of the system corresponding to the conductors of the
pyrometric harness.
(3) Faulty monitoring harness connector
- Check wiring of monitoring harness connector.

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STARTUP
1. After 12 hours of operation, the safety system stops the engine, temperature t4 does not reach 220 °C
A. Fuel filter clogged
- Check the filter.

- Replace the filter.
B. Injection wheel clogged
- lnspect the wheel.

- Clean wheel orifices.
C. Faulty leak solenoid valve
- After 2 to 5 seconds of purge, check if fuel no longer flows through the solenoid valve outlet
orifice. Check operation of the coil as described in para D.
- Replace solenoid valve.
D. Faulty coil of leak solenoid valve
- Check electric power supply.

Check its operation by replacing it with a new coil.
E. Faulty coil of acceleration solenoid
- Check the coil electric power supply.

Check its operation by replacing it with a new coil.
F. Faulty acceleration solenoid valve
- Check coil operation.

Check solenoid valve operation by replacing it with a new one.
G. Startup unit failure
- Check its electric power supply.

Check its operation by replacing it with a new startup.
- Send the startup unit for repair.
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H. Control unit failure
- Check its electric power supply.

Check its operation by replacing it with a new control unit.
- Send the control unit for repair.
I. Monitoring harness failure
- Check for presence of voltage at the terminals of the system connector corresponding to the
missing power supply of the system element.
J. Faulty monitoring harness connector

2. During startup, the safety system stops the engine, temperature t4 exceeds the maximum value of
630 °C
A. On giving the startup order, for the first 2 to 5 seconds, the leak solenoid valve which is open
bleeds the fuel system. If the valve remains blocked in the closed position, the fuel is sprayed
inside the combustion chamber in which it accumulates and causes overheating or an explosion
during the ignition sequence which takes place after the 2 to 5 seconds of purge.
- Check if fuel flows after air exhaust through the leak solenoid valve outlet orifice for 2 to 5
seconds which follows the startup order.
- Replace the solenoid valve.
B. On startup and at shutdown of the engine, blockage in the closed position of the purge valve
cancels the effect of the valve which must evacuate unburnt excess fuel at the bottom of the
turbine casing. This excess which is rather important after an aborted startup is often the cause of
an excessive rise in temperature t4 of exhaust gases or even the cause of engine ignition by
explosion at the next startup.
- Check if air under pressure escapes the purge valve, during the end of shutdown or at the
beginning of startup of the engine.
- Clean or replace the valve or the faulty component of the valve.
C. Startup unit failure
- Check the unit electric power supply.

- Check its operation by replacing it with a new unit.
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D. Faulty control harness
- Check for presence of voltage at the terminals of the harness connector corresponding to the
startup unit power supply.
- Replace the system.
E. Faulty control harness connector

F. Solenoid valve blocked in "open" position
- Check its operation by replacing it with a new valve.

3. At 55% of nominal speed (950 rpm), the electric power supply of the starter is not cut off
A. Faulty magnetic sensor
- Check for presence of power supply at the terminals of the sensor during operation.
- Replace the sensor.
B. Faulty monitoring harness
- Check if the output voltage at the magnetic sensor terminals is present at the general
connector terminals of the harness corresponding to sensor conductors.
C. Faulty monitoring harness connector

4. The engine does not reach its rotation speed of control unit takeover (97% of nominal speed)
- Check the filter condition.

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B. Injection wheel blocked
- Inspect injection wheel.

C. Startup unit failure
- Check its operation by replacing it with a new unit.

D. Control unit failure
- Check control unit operation by replacing it with a new one.

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CONTROL
1. On takeover of control unit, the safety system stops the engine, the engine rotation speed is less than
the limit speed at 95% of nominal speed
A. Incorrect adjustment of "min." cam of control unit
- Actuate the faster control lever and check if correct operation is obtained.
- Send the control unit for repair to be adjusted.
B. Faulty charge pressure switch
- Check its correct operation by replacing it with a new pressure switch.
2. The rotation speed exceeds the maximum speed at 109% of nominal speed, the safety system stops
the engine
A. Incorrect adjustment of "max." cam
- Actuate the slower control lever and check if correct operation is obtained.
- Send the control unit for repair to be adjusted.
B. Fuel metering valve blocked in "open" position
- Check its operation and replace it with a new control unit.

3. After takeover of the control unit, engine rotation speed decreases and becomes lower than 95% and
the safety system stops the engine
A. Faulty load solenoid valve coil
- Check coil electric power supply.

Check its operation and replace it with a new coil.
B. Faulty load solenoid valve
- Check coil operation as in para A.

Check its operation by replacing it with a new solenoid valve.
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C. Faulty control harness
- Check for presence of charge voltage at the terminals of the harness connector corresponding
to the charge solenoid valve power supply.
D. Faulty control harness connector

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OPERATION
1. By actuating the "faster" or "slower" control lever, the rotation speed does not vary
A. Control unit failure
- Check presence of voltage at the terminals of the control harness connector corresponding to
the electric motor power supply.
B. Faulty control harness
electric motor power supply.
C. Faulty control harness connector

2. By actuating the "faster" or "slower" control lever, the rotation speed becomes greater than the
maximum speed or less than the minimum speed which are 109% and 99% at no-load, of nominal
speed
A. Incorrect adjustment of "max." and "min." cams
- Adjust "faster" or "slower" control lever to return to initial speed and check in this case if the
engines operates correctly.
- Send in the control unit for repair to be adjusted.
3. On loading the alternator, the rotation speed decreases and the safety system stops the engine, the
speed is less than 95% of nominal speed
- Check the fuel filter condition.

B. Injection wheel blocked
- Inspect injection wheel.

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C. Control unit failure
- Check its operation by replacing it with a new control unit.

4. On loading the alternator, the rotation speed of the engine decreases abnormally without being less
than the minimum speed of 95% of nominal speed
See para 3.
5. On loading the alternator, the rotation speed of the engine does not decrease proportionally to the load
A. Control unit failure
- Check operation by replacing the control unit with a new one.

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LUBRICATION SYSTEM ANOMALY

TOXIC. IT CAN BE ABSORBED BY THE SKIN AND PENETRATE IN
THE HUMAN BODY. PROTECT HANDS WITH SYNTHETIC RUBBER
GLOVES AND THE FACE WITH A SCREEN OR GOGGLES.
1. The pressure is less than minimum pressure of 700 hPa, the safety system stops the engine
A. Oil pump failure
- Check oil outlet pressure of pump.

- Send the lubrication unit for repair.
B. Oil missing in tank
- Check oil level.

- Top up with oil.
C. Oil missing in tank due to excessive consumption
- Check for normal consumption after topping up with oil.

- See para 5.
D. Faulty low oil pressure switch
- Check its operation and replace it by a new pressure switch.

- Purge the pressure switch or discard the faulty pressure switch.
E. Faulty monitoring harness
low oil pressure switch power supply.
F. Faulty monitoring harness connector

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2. The temperature is greater than max. temperature of 90 °C. The "max. oil temperature" alarm is
triggered
A. Oil cooler clogged
- Check condition of oil cooler.

- Clean oil cooler.
3. No oil temperature rise
A. Faulty probe
- Check probe electric power supply.

- Replace the probe.
- Check for presence of voltage at terminals of harness connector corresponding to the probe
power supply.
C. Faulty monitoring harness connectors

4. Temperature exceeds 90 °C without the "max. oil temperature" alarm being triggered
A. Faulty thermal switch
- Check thermal switch electric power supply.

- Replace the thermal switch.
- Check for presence of voltage at terminals of harness connector corresponding to the thermal
switch power supply.
- Replace the system.
C. Faulty monitoring harness connector

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5. Excessive oil consumption
A. Faulty external tightness seals or rings
- Check that there are no external leak.

- Eliminate the leak by replacing the faulty element, top up oil level in tank.
B. Faulty internal seals
- Check external oil system as per para 5.A.

6. Presence of fuel in the oil
A. Saturated oil
- Check fuel dilution rate in oil.

- Drain and fill the engine completely.
B. Faulty fuel injector connector
- Check if oil level has increased in tank.

- Send the connector for repair.
C. Engine failure
- After replacing the injector connector by a new one, check if there is still an increase in the oil
tank level.
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OTHER ANOMALIES
1. General overheating of the engine, due to either high oil temperature safety system, exhaust gas high
temperature safety system, or fire sensors
A. Sleeve failure
- Check that the sleeve is open during engine operation.

- Replace the flap actuator of the sleeve.
B. Engine failure
- See chapter VENTILATION para 2.
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POWER DRIVE
GENERAL
Power drive of the ASTAZOU IV M1 takes place at the front of the engine according to its longitudinal
axis.
The mechanism required for this operation consists of two main parts:
- The reduction gearbox (3) comprising a series of three steel pinions (1) is housed in a casing (2)
described in chapter 72-80-02.
- The torque limiter (5) is housed in a connection casing (6) which is also used to secure the engine
to the alternator.
These two parts are connected together by means of a sleeve (4).
Figure 1 – Power drive
Page 1
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ASTAZOU IV M1
MAINTENANCE MANUAL
POWER DRIVE
CONNECTION CASING
1. General
The connection casing envelops the torque limiter system and is used to secure the engine to the
alternator. Since the engine is maintained in a balanced position, it is designed in such a way as to
support the stress resulting from this assembly. It is made up of several elements assembled by
welding.
2. Description
A. Perspective view (Figure 1)
The connection casing is formed by an annular envelope (3) fitted with two flanges:
- A drilled flange (1) at the front, designed to secure the engine on the alternator.
- A drilled flange (4) at the rear designed for assembly with the oil tank casing. It is circled by a
centering rib.
Three threaded sockets are welded on top of the envelope and the rear flange. They are intended
to house the attachment support bars for the fire extinguisher.
Figure 1 - Connection casing
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B. Sectional view (Figure 2)
Assembly of the connection casing (1) with the oil tank (9) is carried out by twenty-four screws (8)
and nuts (7). The engine is secured to the alternator (2) by twenty-four screws (3). Two O-rings
(10) and (11) ensure casing tightness. A duct (12) enables oil return from the connection casing
to the reduction gearbox casing.
A tapped boss (6) welded under the casing receives the blanking plug (5) fitted with a seal (4).
The casing is drained through this orifice.
Figure 2 – Connection casing
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CONNECTION CASING
1. Removal-installation of connection casing
A. Purpose
- Case of oil leak.
B. Means required
(1) Tools
- Hoisting ring No. 8813994000.
(2) Spares
201 5 O-ring 72-11 1 7
(3) Products
- Solvents.
- Mastinox compound 6856 K/D 150/2.
- Engine oil.

GOGGLES.
(1) Remove the turboshaft engine (see 71-00-02 pages 201 to 203).
(2) Remove the torque limiter (see 72-10-02 pages 201 to 203).
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D. Removal (see Figure 201)
(1) Remove the extinguisher (see 26-20-01 pages 201 to 203).
(2) Remove the 3 extinguisher support bars.
(3) Install the hoisting ring (3) on two of the three support bar attachments (the hoisting ring
must be located on the alternator side with respect to its two attachment screws).
(4) Sling and slightly tension with lifting beam.
(5) Unscrew and remove 24 attachment screws and washers (2) from the casing (1).
(6) Take out the connection casing by means of 3 of the 24 screws installed in the 3 tapped
holes of the flange (4).
(7) Discard the O-ring (5).
Figure 201 - Removal-installation of connection casing
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E. Installation (see Figure 201)
(1) Clean the mating faces with a solvent and dry.
(2) Install the new O-ring (5). Apply some engine oil on the casing bore in contact with seal.
(3) Apply a light film of Mastinox compound to the flange (4) bearing surface and that on the
alternator side.
(4) Hook and lift the casing with the lifting beam.
(5) Position the casing and install it being careful with the fitting of the seal (5).
(6) Apply Mastinox compound to the 24 attaching screws (2) and install them equipped with their
lock washers. Tighten to a torque load of 3.5 daN.m.
(7) Remove the hoisting ring (3).
(8) Install the 3 extinguisher support bars. Tighten.
(9) Re-install the extinguisher (see 26-20-01 pages 201 to 203).
(1) Install the torque limiter (see 72-10-02 pages 201 to 203).
(2) Install the turboshaft engine (see 71-00-02 pages 201 to 203).
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POWER DRIVE
TORQUE LIMITER
1. General
The purpose of the torque limiter is to declutch the engine alternator connection when the torque
supplied by the engine becomes greater than a certain limit value. In practice, the torque limiter
intervenes during accidental blockage of the alternator. This prevents engine damage caused by an
instantaneous shutdown.
A hub (19) is maintained on the alternator shaft by a notched nut (10). A ring (6) is connected to the
output wheel of the reduction gearbox by a drive sleeve (14).
Figure 1 – Torque limiter
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The hub and ring have axial splines in which two series of splined disks (4) and (5) are engaged. One
series is integral with the hub and the other with the ring through the splines. These disks are applied
against each other by 21 springs (20) between two flanges (3) and (13). Connection by adherence
between these disks enables transmitting engine rotation to the alternator through the hub and disk
holder ring.
The flange (13) is maintained on the hub by three screws (12).
The ring is secured to the sleeve by six screws (15). The assembly is guided in a shoulder inside the
sleeve located between a ring (8) and a spacer (7), these are maintained on the hub against the flange
(13) by three screws (9).
The springs (20) centered by flange (3) bosses bear on a disk (2) screwed into the hub. Spring tension
is adjusted by disk movement obtained by screwing or unscrewing the latter. A second ring (1) is
screwed onto the hub after the first. Six screws (18) cross this ring and are housed in the first ring.
They are used to stop rotation of the latter by blocking the threads of the two disks by tightening.
These screws also cross flange (3) to drive it in rotation during an adjustment. This adjustment is
finally achieved by loosening screws (18) and rotating the flange assembly, i.e. first ring, second ring.
Loosening of the screws is limited by a nut (17) screwed onto each screw and locked by a pin (16).
The sleeve comprises internal splines which engage into those of the output wheel for rotation
connection.
The rotation connection of the hub and shaft of the alternator is achieved by a key (11).
Drillings in the hub provide for disk lubrication.
3. Operation
During normal operation of the engine and alternator, the torque limiter ensures connection between
these two assemblies.
During accidental blockage of the alternator, the disks slide with respect to each other by means of
lubrication oil in spite of the spring pressure. This results in ring and hub decoupling, and consequently
of the engine and alternator.
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TORQUE LIMITER
1. Removal-installation of torque limiter
A. Purpose
- Operating anomalies.
- Adjustment.
- Removal of connection casing.
B. Means required
(1) Tools
- Extractor 8814213000 (used with extractor FACOM U27 AS 3).

- Handling bracket 8814700000.
- Tightening tool 8814333000 (used with torque wrench with a minimum capacity of
8 daN.m. and torque multiplier by 4: LW 750-4X-SOVECO).
- Installation tool 8814332000.
(2) Products
- Loctite 242 (normal thread lock).

- Solvents.
(1) Remove the turboshaft engine (see 71-00-02 pages 201 to 203).
D. Removal of equipped torque limiter (see Figure 201)
(1) Install the handling bracket. Sling and slightly tension the lifting beam.
(2) Using special tool, unscrew and remove the nut (2) attaching the torque limiter to the shaft
(1).
(3) Remove the limiter using the extractor.
(4) Tilt over the limiter on its handling bracket and place it on a work table or an adjustment
base.
(5) Remove the handling bracket.
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E. Removal - installation of drive sleeve (case of replacement) (Figure 201)
(1) Remove the six screws (3) attaching the drive sleeve (6).
(2) Loosen and remove 3 screws (8) attaching the ring (9) and spacer (10).
(3) Remove the ring (9) the sleeve (6) and the spacer (10).
(4) On the new limiter, remove 3 of the 6 screws (5) attaching the flange (4) (location of
3 attaching screws (8)).
(5) Install the spacer (10) on flange (4).
Figure 201 - Replacement of torque limiter
(6) Install the drive sleeve (6). Install the 6 attaching screws (3) and tighten to a torque load of
10 daN.m.
(7) Install ring (9) by coinciding the 3 attachment holes with the 3 holes of flange (4) previously
released.
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by the notice appearing on the information page 72-10-02 1983
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(8) lnstall the 3 attaching screws (8) equipped with new locks. Tighten the screws to a torque
load of 6 daN.m. Lock and anchor the locks.
F. Installation of equipped torque limiter (see Figure 201)
(1) Install the handling bracket, slang and lift using lifting beam. Tilt over the limiter to return it to
the installation position.
(2) Position the torque limiter on the shaft (1) in such a way as to coincide the key (4) and its
housing.
(3) Fit the limiter completely using the tool.
CAUTION: APPLY LOCTITE THREAD LOCK ON ATTACHMENT NUT THREADS

(2) (See detail in Figure).
(4) Install the attachment nut (2) and tighten to a torque load of 30 daN.m. using tool.
(5) Remove the special tool and the handling bracket.
(1) Install the turboshaft engine (see 71-00-02 pages 201 to 203).
2. Adjustment of torque limiter
A. Purpose
- No transmission of rotation torque (slippage).

- Temperature abnormally high.
B. Means required
(1) Tools (see Figure 202)
- Tooling is to be supplied by the user (torque multiplier - dial torque wrench - special end
fitting - immobilization tool).
NOTE: The torque multiplier must have a capacity of at least 300 daN.m.
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(1) Remove the torque limiter (see 72-10-02, pages 201 to 203).
D. Procedure (see Figure 202)
(1) Install the limiter on the immobilization tool (1) using the lifting beam and handling bracket.
(2) Install tools (special end fitting (4), torque multiplier (5), dial torque wrench).
Figure 202 - Adjustment of torque limiter
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(3) On the dial of the torque wrench, measure the torque required to make the limiter disks slip
as follows: 260 daN.m. ± 15% (or ± 40 daN.m.).
CAUTION: TAKE ACCOUNT OF TORQUE MULTIPLIER RATIO.
(4) Completely unscrew screws (3) to disengage the spring holder disk (6) and to release the
disks (2).
(5) Adjust by turning the disk (9) which moves the adjustment nut (8) at the same time.
NOTE: By turning the disk in the clockwise direction, the slippage torque value is
increased; this value is decreased when turning the disk counterclockwise. At
the end of adjustment, make sure that play exists between the adjustment nut
(8) and the spring holder disk (6).
(6) Thoroughly screw in screws (3) to release the springs (7) and thus make the disks (2) bear
on each other.
(7) Tighten screws (3) to block nut (8).
(8) After each adjustment, carry out a measurement (see step 3) until the desired value is
obtained.
(9) Remove the adjustment tools.
(10) Install the handling bracket.
(11) Sling and Iift using lifting beam.
(1) Install torque limiter (see 72-10-02 pages 201 to 203).
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POWER DRIVE
REDUCTION GEARBOX
1. General
The reduction gearbox is of the single intermediate train coaxial type. Its reduction ratio of 24.0621
enables reaching an output speed of 1,087 rpm from an engine rotation speed of 43,500 rpm.
2. Operation (Figure 1)
A driving pinion (2) receives rotation movement from the engine shaft line by means of a coupling
sleeve (4) through a drive sleeve (3) (see chapter 72-30-02, paragraph 5). The movement is then
transmitted after reduction to an output wheel (1) by means of an intermediate pinion assembly (9).
A pinion (10) housed and maintained in the intermediate pinion assembly drives a pinion train which is
used for driving engine accessories (see chapter 72-60-01).
- Pinion (8), intermediate-starter,

- Pinion (7), double, oil pump drive,
- Pinion (5), control unit drive,
- Pinion (6), intermediate pinion-governor.
Figure 1 – Reduction gearbox
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3. Hub casing (Figure 2)
The driving pinion and the output wheel are installed on a steel hub casing formed by a threaded front
cylindrical bearing (1), followed by a central conical section (2) and terminated by a drilled attachment
flange (3) with hollow centering receptacle (4).
It has a central boring (8) with stepped diameters in which the driving pinion and the fuel system
injector connector are maintained (see chapter 73-40-01 paragraph 3). The output wheel is maintained
on the front bearing. A large milled notch (7) in the lower part of the cone enables passage of the
intermediate assembly wheel for meshing with the driving pinion.
A series of circular splines (6), drillings (5), and different millings is made for lubricating certain
elements and the fuel duct (see chapters 72-80-04 and 73-40-03).
Figure 2 – Hub casing
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4. Driving pinion (Figure 3)
The driving pinion (4), which is hollow to allow passage of the fuel pipe is cut on a shaft whose ends
include threads and a bearing surface on which two roller bearings (2) and (6) are secured for rotation
purpose. These bearings are held in the central bore of the hub casing (12). They are installed as
follows:
- They are maintained by the driving pinion, the one on the left (2) by a nut ring (1) and that on the
right (6) by a drive sleeve (9); these parts are screwed on the pinion shaft.
- They are positioned in the hub casing by a circlip (3) against a shoulder for bearing (2) and
between a circlip (5) and a cover (7) maintained on the hub casing by six screws (8) for bearing (6).
The roller bearings do not ensure axial guidance. This guidance is carried out by two thrust
washers (11) maintained between the pinion and the bearings. They frame meshing of the pinion with
the driven wheel (10) of the intermediate pinion assembly in order to limit translation movement of the
pinion to that of the intermediate pinion assembly.
Figure 3 – Driving pinion
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5. Output wheel (Figure 4)
The I-shaped output wheel (2) comprises a rim on which the teeth are cut and a hub on which a
splined ring (3) is welded, providing continuity of the movement towards the torque limiter.
At the end of the hub casing (1), the cylindrical bearing surface is fitted with two conical roller bearings
providing rotation of the wheel in which they are mounted. These bearings comprise cones (11)
separated by an adjustment washer (8) and cups (7) separated by a washer (6).
The cones are maintained against a shoulder of the hub casing by a nut ring (9) through a washer
(10).
The cups are maintained against a shoulder of the wheel by a nut ring (5) through a washer (4).
Figure 4 – Output wheel
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6. Intermediate pinion assembly (Figure 5)
The intermediate pinion assembly comprises an intermediate wheel (6) and an intermediate pinion (5)
welded together and forming a shaft terminated by two bearing surfaces each fitted with a roller
bearing (3) and (16). Three machined pins (11) at the end of this shaft drive the pinion (13) by
meshing into slots milled in the latter. This pinion is cut in the hollow shaft end (4) which is housed and
maintained in the intermediate pinion assembly. A ball bearing (15) located on the pinion (13) ensures
translation shutdown not performed by the roller bearings.
The external ring of the roller bearing (3) is secured in a housing of the oil tank casing (19) and is held
in place by a cover (17) retained by six screws (18). The external rings of the roller bearing (16) and
ball bearing (15) are held by a cage cover (7) against a cage (10) by means of an adjustment
washer (9). The overall assembly is secured to the air inlet casing (12) by six screws (8). The cage
(10) closes a blade device in the air inlet casing thus forming a cavity used by the lubrication system
(see chapter 72-80-04 paragraph 2). An O-ring (14) ensures tightness.
Figure 5 – Intermediate pinion assembly
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A ring nut (1) screwing onto the shaft (4) is used to successively secure against the pinion (13) and by
means of a ring (2) the inner ring of the roller bearing (3), the intermediate pinion assembly (5) and (6),
the inner ring of the roller bearing (16) and ball bearing (15).
7. Installed assembly and accessories (Figure 6)
The hub casing (1) which acts as support for the driving pinion and the output wheel is secured to the
air inlet casing (5) by sixteen screws (9). Two O-rings (4) ensure tightness of the circular lubrication
duct formed by the base groove. The injector connector (16) is secured in the central bore by three
screws (15).
A nozzle (6) is used for lubricating the rear bearing of the driving pinion and channels oil to the front
bearing of the axial compressor. These two ends of cylindrical shape fitted with O-rings (8) engage
into a drilling of the hub casing on one side, and in a drilling of the air inlet casing followed by a drilling
of the hub (7) on the other. A flat on its shoulder enables orientation.
A tube (14) serving as lubrication duct crosses the pinion (11). It is maintained by its ends which, fitted
with tightness O-rings (12), engage in the blades of the oil tank casing (13) and of the cage (10).
A nozzle (2) housed in the hub casing is used for lubricating the driving pinion/driven wheel meshing. It
crosses a hub casing bushing and is secured at this point by a cover (3). A shoulder allows orientation
with respect to the cover.
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Figure 6 – Reduction gearbox

1991
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AIR INLET
GENERAL
The inlet of air required for operation of the ASTAZOU IV M1 engine takes place through an opening
at the top of an air inlet casing (2). This casing comprises the central part of the engine between the
turbine casing (3) and the oil tank casing (1). It ensures correct air flow to the axial compressor (5) that
it surrounds with the centrifugal compressor (4).
The air inlet also comprises a pipe system and nozzles (6) for cleaning the compressors.
Figure 1 – Air inlet

1991
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AIR INLET
AIR INLET CASING
1. General
The air inlet casing is the main part of the engine structure. It has a massive and rigid shape and
comprises the central part on which most of the other blocks of the engine and its accessories are
secured. It supports the covering attachment structure and enables engine lifting.
2. External view (Figure 1)
The air inlet casing comprises a U-shaped body (3) and an accessory support flange (1) mounted on
the front.
Eight tapped bosses (2) border the side faces of the body. They are used to attach the enclosure
structure. The left side face comprises a rectangular boss on which an identification plate is secured
(5) by means of six rivets (4).
The accessory support flange is bordered by a flange (7) for attaching the oil tank casing. The hub
casing of the reduction gearbox and hub of the axial compressor are secured on two concentric
flanges (8) and (9) with a bore (6) through which the engine shaft line crosses.
Figure 1 - Air inlet housing
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A flange (10) tangent to flange (8) supports the rear bearing of the intermediate pinion assembly.
At the bottom part of the flange, four flanges (11) are used to secure accessory driving pinions. The
left flange is partly interrupted by a bore (12) in which the relay box is secured.
(See chapters 71-40-01, 72-80-01, 72-10-02, 72-30-01, 72-60-01, 72-60-02).
3. Sectional view (Figure 2)
The front face of the body comprises a bladed drilling (12) and four tapped drillings (11) drilled into the
machined blades over a concentric diameter of the bore (10). These machinings are used to attach the
cleaning manifold.
The air comes in from the top of the body through a rectangular opening bordered by a flange (1) on
which an air tightness assembly is secured.
The rear face of the body includes a large opening circled by a flange (2) for attachment of the rear
parts of the engine.
A swelling at the bottom part of the body is drilled with three holes (4) through which three lubrication
duct pass. Two tapped sockets (3) are screwed on either side for attaching a connection strip. Foreign
liquids falling at the bottom of the casing are evacuated through two drilled holes (5).
On the rear face of the flange, tapped holes two of which equipped with studs (6) are used for securing
accessories.
At the base of the flange, two drilled holes (8) fitted with sockets (7) are used as oil flow ducts. Other
machinings (9) at different locations also allow lubrication oil to flow.
(See chapters 72-20-02, 71-10-01, 72-40-01, 72-80-05, 72-60-02, 72-80-03, 73-30-01, 72-80-04).
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Figure 2 – Air inlet casing
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AIR INLET
SPRAYING MANIFOLD
1. General
Specially designed as concerns the materials used for marine environment, this engine is supplied by
air processed by sea spray coalescer filters (chlorine content < 0.01 ppm weight).
However, to avoid compressor clogging and to forestall possible oxidation, the engine is fitted with a
system for spraying washing or inhibition products in the air path.
2. Installation
The system comprises a spraying manifold and supply pipes.
A. Spraying manifold
(1) Manifold (Figure 1)
The manifold consists of two stainless steel pipes (2) connected to a supply connector (1).
These two pipes comprise a manifold assembly of six nozzles (3).
Figure 1 - Spraying manifold
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(2) Nozzles (Figure 2)
The nozzles consist of three parts conditioning the liquid to obtain better spraying of the latter.
Each nozzle comprises a spiral (2) and a pellet (3) housed in a sleeve (1).
The pellet has a machined conical drilled hole for spraying liquid.
The spiral makes a rotating movement to the liquid thus having a swirling spray.
Assembly is obtained by crimping the sleeve.
Figure 2 - Nozzle
(3) Manifold attachment (Figure 3)
Figure 3 – Assembly of spraying manifold
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The manifold (4) is maintained by four clamps (6) secured by four screws (5) on the inner front
face of the air inlet casing (3). The connector crosses the partition of the casing and is maintained
by a nut (1) equipped with a washer (2). The nozzles are directed towards the axial compressor
inlet (7).
B. Supply pipes (Figure 4)
Washing is performed from the exterior of the engine enclosure using a pipe (2) which connects
the washing manifold to the front frame (9). The pipe is connected to an angle connector (1)
screwed onto the manifold connector and on a set of fixed parts on the front frame of the
enclosure. This set comprises a nipple (5) secured on the frame by a nut (4) on which two angle
connectors are screwed. One angle connector (3) is connected with the pipe (2) and the other
angle connector (6) is connected with an end fitting (7) for connection of a washing unit pipe
attached by a clamp (8).
Figure 4 – Supply pipes
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AIR INLET
1. Washing of air path
A. Purpose
This operation is intended to limit compressor clogging and eliminate saline deposits on the
engine air path when the engine is used in a marine environment. This operation always precedes
any protection operation.
B. Means required
(1) Special tools (see installation example Figure 201)
The spraying manifold (built into the engine) must be connected to the different equipment
items remaining at user's cost (tanks, valves system, filter and pipes).
NOTE: Tanks (1) and (2) must be pressurized with compressed air at 6,000 hPa.
(2) Products
- ARDROX 6342 (ex. 9PR4L).

- ISOPROPYLALCOHOL (NON TOXIC) or if not available METHANOL (DEADLY
POISON).
- DISTILLED WATER or if not available demineralized or potable water.
WARNING: CERTAIN PRODUCTS ARE NOT ONLY CORROSIVE BUT

ALSO VERY TOXIC WHATEVER THE MODE OF
ABSORPTION. TAKE ALL NECESSARY SANITARY
PRECAUTIONS SUCH AS WEARING GLOVES, MASK,
SPECIAL CLOTHING, ETC.
(1) Prepare four litres of a mixture prepared according to the proportions indicated in the table
below; the latter vary according to ambient air temperature (t°).
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NOTE: The percentages are indicated in volume.
Temperature Washing product Water Isopropyl alcohol

or methanol
to > + 5°C 2% 98 %
+ 5° > to > - 8 °C 2% 80 % 18 %
- 8° > to > - 24 °C 2% 65 % 33 %
NOTE: ARDROX 6342 is a corrosion inhibitor on metal equipment in contact with

solutions with sea water and facilitates solution mixing of salt deposits.
- Distilled water or demineralized water are used as diluting agents.
- Isopropyl alcohol or methanol are used for lowering the mixture
freezing point if necessary.
(2) Vigorously star to obtain a consistent mixture and pour it in the system tank (1) (Figure 201).
CAUTION: METALLIC TANKS ARE PROHIBITED FOR PRESERVING PURE OR

DILUTED WASHING PRODUCTS.
PURE WASHING PRODUCTS MUST BE PRESERVED IN THEIR
ORIGINAL PACKING CORRECTLY CLOSED.
THE MIXTURE MUST BE PRESERVED IN A PLASTIC TANK OF
POLYETHYLENE OR POLYPROPYLENE TYPE WITHOUT CHLORINE
CONTENT.
NOTE: The washing product diluted and ready for use can be prepared 2 months in
advance. The product is biodegradable in air but it can be stored without
any special precautions for 5 to 6 days. For longer storage periods, the tank
must be opaque and closed tight.
Figure 201 - Installation example for washing and protecting air inlet
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D. Procedure
(1) Make sure the mixture is available in the tank of the washing unit (quantity and pressure).
(2) Ensure that the air inlet and exhaust cover flaps are open.
CAUTION: THE RESIDUAL TEMPERATURE t4 OF THE ENGINE MUST BE LESS

THAN 100 °C. AS FAR AS POSSIBLE, IF OPERATING CONDITIONS SO
ALLOW, WAIT UNTIL THE ENGINE COOLS DOWN NATURALLY. THIS
WILL AVOID DISCHARGING BATTERIES WHEN CARRYING OUT
SUCCESSIVE COOLING OPERATIONS.
(3) Start washing by proceeding as follows:
- Start a cooling operation and simultaneously engage the starter, open the valve for
product flow towards the engine.
- After 20 seconds of cooling, cut off the starter and simultaneously close the product inlet
valve.
- Wait until the engine has stopped completely.
(4) Repeat the above operation three times successively.
NOTE: At the end of the 3rd injection operation, the 4 litres of product must have been
completely sprayed into the engine. Otherwise, check the system and in
particular the protection filter and the spraying manifold.
(5) Drain the washing system assembly by blowing dry compressed air for 15 to 20 seconds.
(6) Ensure that the air inlet and exhaust cover flaps are closed.
NOTE: At the end of the washing operation, the exhaust gas temperature measurement
thermocouples are wet and can give a false indication.
If startup must be performed within the hour which follows the washing
operation, two cooling operations will have to be previously performed.
The second cooling operation can be the one which mandatorily precedes
startup.
E. Periodicity
(1) Every 50 hours of use.
(2) During each shutdown when the duration provided for non operation is greater than 12 hours
or unknown.
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2. Protection of air path
A. Purpose
The purpose of this operation is to spray an inhibitor product inside the air path (the compressor in
particular) to immunize the surfaces against corrosion.
B. Means required
(1) Special tools
(See 1. B. Washing)
(2) Products
The products necessary are given in chapter 71-00-03 para 4.
WARNING: INHIBITION PRODUCT MISTS ARE HIGHLY FLAMMABLE.

THEREFORE TAKE ALL NECESSARY PRECAUTIONS
DURING THEIR HANDLING (AVOID HOT POINTS AND
FLAMES).
C. Preliminary steps (Figure 201)
(1) Pour the product in a supply tank (2) (0.1 litre per engine) (Figure 201).
NOTE: The inhibition product must be preserved in a perfectly tight tank to avoid solvent
evaporation.
D. Procedure
NOTE: The inhibition procedure (protection) must always be preceded by a washing

operation in an interval of time between 50/100 of an hour and 4 hours.
(1) Make sure the inhibition product is available in the supply tank (quantity and pressure).
(2) Ensure that the air inlet and exhaust cover flaps are open.
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(3) Start inhibition operation by proceeding as follows:
- Start a cooling operation and 5 seconds later, engage the starter, open the supply valve.
- Once the required quantity of product is sprayed into the engine, close the supply valve
and cut off the starter.
(4) Drain the pipes and injection manifold by blowing dry compressed air for 15 to 20 seconds.
(5) Ensure that the air inlet and exhaust cover flaps are closed.
E. Periodicity
(1) During each shutdown, when the duration provided for non operation is greater than 1 week
or unknown.
(2) Every month in the event of prolonged shutdown.
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COMPRESSION
GENERAL
The compressor of the ASTAZOU IV M1 is a compressor with two compression stages.
- An initial compression is performed in an axial compressor (4).

- Final compression is provided by a centrifugal compressor (8).
The two compressors are located in a counter casing (7) which is housed in the air inlet casing (2)
between the reduction gearbox (1) and the combustion chamber (9).
Figure 1 – Compression

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For good air flow, the swirling air leaving the compressors crosses a rectifier (5) and two diffusers (10)
and (11).
In addition, the compressor assembly comprises a front bearing holder hub (3) of the axial
compressor, a rear bearing holder cover cage (14) of the axial compressor, a bearing holder
compressor casing (6) of the centrifugal compressor and a centrifugal compressor cover (12).
At nominal operation of the engine and under standard atmospheric conditions, the compression
assembly outputs an air mass of 2.5 kg per second at a pressure of 5.8 bars.
Two coupling sleeves (13) and (15) enable connection between the two compressors on one hand and
on the other connection between the axial compressor and the reduction gearbox.
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COMPRESSION
COMPRESSOR COUNTER-CASING
1. General
The compressor counter-casing consists of three forged steel parts assembled by welding. It
envelopes the two compressor assembly and parts which complete them. It ensures partly their
securing and their attachment to the air inlet casing.
The compressor counter-casing comprises a central cylindrical part (3) drilled with three holes (2) for
passage of lubrication ducts.
Figure 1 – Compressor counter-casing
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At the front, a bellmouth (1) improves air flow towards the axial compressor.
At the rear, a large collar (4) fitted with a drilled flange (5) is used for its attachment on the air inlet
casing (see chapter 72-40-01).
The bottom section of the central part is fitted with two welded and tapped sleeves (7). They are used
for attaching a connection strip (see chapter 72-80-05).
A ring drilled with eighteen holes (6) is added to strengthen the mounted assembly.
The front part of the central cylinder is internally covered with a fine coat of a mixture of polyester resin
aluminium and silicon (8). At this point, rotation of the axial compressor mobile takes place. It thus
provides air guidance and tightness.
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COMPRESSION
AXIAL COMPRESSOR
1. General
The axial compressor is a single stage compressor. It comprises two distinct parts: the mobile part and
the fixed part. Each part comprises several components
2. Mobile part
A. Rotating assembly (Figure 1)
The mobile part basically consists of the rotating assembly. It consists of a wheel (4) and a shaft
(3) in one block.
The wheel comprises a rim (5) on periphery of which blades (6) are cut.
The hollow shaft to allow passage of a fuel pipe includes at both ends splines (2), threading (1) a
shoulder (7) one at the front and two at the rear.
Figure 1 – Rotating assembly
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B. Bearings (Figure 2)
The rotating assembly (4) is installed on two bearings:
- front bearing (3),

- rear bearing (5).
A locked hood nut (1) maintains each bearing with the drive sleeve (2) or (6) on the rotating
assembly shaft.
Figure 2 - Rotating assembly - bearing assembly

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(1) Front bearing (Figure 3)
The new front bearing is intended to reduce sensitivity of the bearing to axial loads by
addition of an oil film between the bearing and housing.
It comprises a housing (5) in which the following are assembled:
- a sealol seal (9),

- a friction ring (8),
- two washers (6) and (7),
- a stop ring (10),
- the bearing (4),
- an adjustment washer (3),
- a spring washer (2),
- the nozzle spacer (11),
- an inner thrust ring (1).
Figure 3 - Front axial bearing

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(2) Rear bearing (Figure 4)
This is a conventional bearing which consists of a housing (6) in which the following are
assembled:
- a washer (1),
- a sealol seal (2),
- a friction ring (3),
- a bearing (4),
- an inner thrust ring (5).
Figure 4 - Rear axial bearing

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C. Front bearing housing (Figure 5)
Made of steel, the housing comprising the front bearing of the axial compressor includes a series
of machinings which provides it the function of bearing lubrication. It consists of a cylindrical
body (1) and a drilled flange (3).
An external groove (2), four longitudinal grooves (7) and an internal groove allow lubrication oil to
flow. Holes (6) drilled in the grooves are used to deposit an oil film around the bearing. In one of
the upper grooves, a spout (5) lubricates the Sealol seal. Two oblong holes (4) milled at the level
of the inner groove ensure oil evacuation from the bottom and oil vapor evacuation from the top.
The body also includes a notch (8) in which the hub key (Figure 8, item (9)) is housed.
Figure 5 - Front bearing housing

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D. Rear bearing housing (Figure 6)
Made of steel, the housing comprising the rear bearing of the axial compressor includes a series
of machinings which provides it the function of bearing lubrication. It consists of a cylindrical
body (1) and a drilled flange (3).
An internal groove and four longitudinal grooves (7) made between two circular grooves (2)
enable lubrication oil flow. In the two upper longitudinal grooves, two millings (5) are machined in
which two spouts (6) lubricate the Sealol seal and the ball bearing respectively. Two oblong holes
(4) milled at the level of the inner groove ensure oil evacuation from the bottom and oil vapor
evacuation from the top.
The body also includes a drilling (9) and a notch (8).
Figure 6 - Rear bearing housing

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3. Fixed part
A. Rectifier (Figure 7)
The rectifier comprises several parts assembled by welding and brazing. It comprises two rings
(3) and (4) on the periphery of which the blades (1) are milled. A centering foot (2) positions the
rings which are centered by a circular rib (6). Welding points make them integral, one with respect
to the other. A ring (5) is brazed on the blade heads. A drilled cellular flange (7) is used for its
attachment.
Figure 7 - Rectifier

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B. Hub (Figure 8)
The front bearing of the axial compressor is assembled in a light alloy hub.
It consists of a bored cylindrical body (3) whose external shape represents a concave then
convex generator from the front to the rear.
The front face includes a centering receptacle (1) drilled with four tapped holes for attachment.
The rear face includes four drilled holes (6) for fitting a centering foot (4) and a spring (5) in each
of them.
A series of drilled holes (7) allows lubrication oil channelling towards the bearing. Two holes (2)
enable oil and oil vapor evacuation originating in the bearing.
A key (9) is secured by two screws (10) into a milling (8) made in the boring.
Figure 8 – Hub

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C. Cover housing (Figure 9)
The rear bearing of the axial compressor is assembled in a light alloy cover housing.
It consists of a bored cylindrical body (1) and a drilled attachment flange (2).
Since both bearings of the axial compressor are identical, they have the same functional
machinings as the hub.
- The front face comprises four drilled holes (7) equipped with centering feet (8) and spring
feet (9). They include a series of drilled holes (6) for lubrication and two holes (10) for
evacuation. A key (4) is secured by two screws (5) in a milling (3) made in the boring.
Figure 9 - Cover housing
4. Assembly and operation (Figure 10)
The hub (3) and cover housing (13) are respectively secured to the air inlet casing (2) and the
compressor casing (11) by four screws (1) and four screws (12).
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The housings (14), rotating assembly bearing supports (6) slide in the hub and cover housing enabling
by means of springs (5) centering of the rotating assembly and ensuring a permanent axial load on the
bearings by pre-loading the ball bearings.
The keys (4) of the hub and of the cover housing engaged in the rear notches of the housings guide
these in translation movement.
Drilled holes for lubrication of the hub and cover housing channel oil towards the housing grooves thus
lubricating the centering mechanism. Evacuation is through oblong holes in the housings followed by
holes in the hub and cover housing.
The counter-casing (8) tops the rotating assembly whose blades graze the internal coating.
The rectifier (9) is housed in the counter-casing and is secured against the compressor casing by four
screws (10).
Tightness is obtained by O-rings (7) on the hub, the housings and the rectifier.
Figure 10 - Axial compressor
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5. Coupling sleeve (Figure 11)
The movement connection between the axial compressor and the reduction gearbox is obtained by a
coupling sleeve (4) formed by a tube grooved internally at its two ends. The grooves engage in those
of the coupling sleeve (2) screwed onto the driving pinion (1) and in those of the driving sleeve (5) of
the shaft of the rotating assembly (6). Two clips (3) maintain it in position.
Figure 11 - Coupling sleeve
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COMPRESSION
CENTRIFUGAL COMPRESSOR
1. General
The centrifugal compressor is used to obtain final air pressure by the centrifugal method. It comprises
a mobile part and a fixed part formed by parts, some of which condition air to obtain its better flow and
therefore better operation.
2. Mobile part
A. Intake wheel and centrifugal impeller (Figure 1)
The mobile part basically comprises the intake wheel and centrifugal impeller assembly made of
steel.
The intake wheel (1) consists of a hub (3) fitted on its periphery with blades (2) at its center with a
bore comprising two shoulders (4). The centrifugal impeller (7) consists of a mounting flange hub
(6) fitted with blades (5) which thin out towards the mounting flange end. The bored hub includes
eight drive claws (9) and the mounting flange, two balancing collars (10). Three centering dowels
(8) are used to position the wheel with respect to the impeller.
Figure 1 – Intake wheel and centrifugal impeller
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B. Shaft nose (Figure 2)
The wheel and impeller assembly (4) is installed on a steel hollow shaft nose (9) for passage of a
fuel tube and the injection wheel.
Its rear end comprises a drilled attachment flange (7).
Its front end comprises splines (2) and a threading (1) for securing a bearing.
At its center, a threading enables screwing in of a ring nut (3) which maintains the wheel and
impeller assembly with a labyrinth ring (8) against the attachment flange.
A pin (6) immobilizes the labyrinth ring. The impeller claws engage in the milled notches (5) of the
nose.
Figure 2 – Shaft nose
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3. Fixed part
A. Centrifugal compressor casing (Figure 3)
The light alloy cast compressor casing consists of an external cone (3) and an internal cone (2)
separated by three formed section arms (1).
The inner cone comprises a drilled flange (7), at the front, which is used to secure the rectifier and
the cover housing of the axial compressor, and a drilled flange (4) at the rear which is used to
secure the bearing of the centrifugal compressor.
The external cone comprises two centering bosses (6) and a drilled flange at the rear for
assembling of the compressor cover. The formed section arms are each drilled with lubrication
channels and two tapped holes for attaching lubricating connectors (see chapters 72-80-04 and
72-80-05).
Figure 3 – Centrifugal compressor casing
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B. Centrifugal compressor cover (Figure 4)
The compressor cover is formed by a cylindrical part (2) and a plate (1) which take the form of the
wheel and impeller.
The cylindrical part comprises a drilled flange (4) bordered by a circular centering rib (5). It is
used for securing the compressor casing.
The plate is bordered by a drilled flange (3) for securing the air inlet casing.
At the center of the plate, a boss (6) drilled with five holes is used for securing the first stage
diffuser.
Figure 4 – Centrifugal compressor cover
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C. First stage diffuser (Figure 5)
The first stage diffuser comprises a front ring (1) on which the blades (3) are milled and a rear
ring (2) brazed on the blade heads.
On each of the rings, five tapped sockets (4) are brazed to enable its attachment to the
compressor cover at the front and attachment of the second stage diffuser at the rear.
Figure 5 – First stage diffuser
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D. Second stage diffuser (Figure 6)
The second stage diffuser comprises a plate (4) and a ring (1) with blades (2) cut on its periphery.
The plate comprises a boss (3) drilled with five holes for securing the first stage diffuser. At its
center, it has a flange (6) on which a set of parts ensuring compressor tightness is maintained.
Against the flange, an externally splined labyrinth (8) is maintained in an internally splined
mounting flange (11) by means of another labyrinth (9). An adjustment washer (12) is inserted
between the flange and the mounting flange. The assembly centered by a pin (7) is maintained by
eight screws (10) which screw into the labyrinth (9). The pin is blocked by a lock plate (5)
maintained by two of the eight screws (10).
Figure 6 – Second stage diffuser
E. Centrifugal compressor bearing (Figure 7)
The centrifugal compressor bearing comprises a ball bearing (8) maintained by a special notched
nut (13) in a steel housing (5). The housing is positioned by four small bosses (6) in a steel
bell (3). The nut is locked in the housing by a pin (14).
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The shaft nose (11) is maintained in the ball bearing by a notched nut (16) which also maintains
on the nose a friction ring (12), an adjustment washer (7), a drive sleeve (15) meshing in the shaft
splines and an adjustment washer (9).
The bell (3) comprises a cylindrical bearing at the front which engages in the inner cone of the
compressor casing (2) and thus prolongs its conical shape. The housing and bell are maintained
by flanges placed on either side of the compressor casing flange. Assembly is obtained by eight
screws (1). The housing is positioned by a centering pin (18).
A series of openings (17) made in the cylindrical part of the housing provides it with a certain
flexibility required for bearing operation.
The rear of the bell forms a housing in which a Sealol seal is located. It ensures tightness by
rubbing against the friction ring. An O-ring (4) also ensures tightness of the bearing.
A tube (19) crosses the housing flange and is secured in one of the bosses. It is used for
supplying oil into the lubrication channels drilled in the housing and the special nut is used for
lubricating the bearing. Notches milled into the flanges of the bell housing and compressor
housing enable oil evacuation at the bottom and vapor evacuation at the top.
Figure 7 – Centrifugal compressor bearing
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4. Assembly of centrifugal compressor (Figure 8)
On either side of the first stage diffuser (8), the compressor cover (7) and the second stage diffuser (9)
are secured each maintained by five screws (10).
Compressor cover positioned by a centering pin (5) and its rib is secured to the compressor casing (4)
by twelve screws (14). The pin is locked by a lock plate (6) maintained by two of the twelve
screws (14).
The compressor casing (4) and the rectifier (2) of the axial compressor are housed in the counter
casing (1). Three O-rings ensure air tightness.
The rotating assembly (13) maintained by the bearing (15) is located between the cover and the
second stage diffuser. Tightness is obtained by friction of the labyrinths (11) against the labyrinth
ring (12).
The lubrication tube (16) of the bearing starts in the cover housing (17) through which oil is supplied.
Figure 8 – Centrifugal compressor
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5. Coupling sleeve (Figure 9)
Movement connection between the centrifugal compressor and the axial compressor is obtained by a
coupling sleeve (4) formed by a grooved tube at each of its ends. The grooves engage with those of
the driving sleeve (1) of the axial compressor (2) and in those of the driving sleeve (6) of the shaft
nose (7). Two clips (3) hold it in position.
A spacer (8) fitted with an adjustment washer (9) connects the two axes. It enables passage of the fuel
tube protection.
Holes (5) are used to evacuate lubrication oil from the connection.
Figure 9 – Coupling sleeve
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COMBUSTION
GENERAL
The air compressed by the centrifugal compressor (1) comes out through the second stage diffuser
(2). It is mixed with fuel sprayed by the injection wheel (3) into the combustion chamber (4) where
combustion of this mixture takes place.
This combustion chamber is delimited by an external mixer (10), a swirl plate (11) and an internal
mixer (9). The assembly is housed in a turbine casing (5). A labyrinth (8) ensures protection of the
turbine shaft (6) and tightness of the chamber.
The burnt gases are then mixed in residual air and expelled into the first stage diffuser (7) of the
turbine.
Figure 1 – Combustion

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COMBUSTION
TURBINE CASING
1. General
The turbine casing is made up of welded elements. It forms the end envelope of the combustion
chamber. In the turbine casing, combustion air flow, dilution and cooling are performed. It forms the
main part, visible at the rear, of the engine and enables attaching its constituent parts.
The turbine casing mainly consists of a slightly bulging cone (13) and two attachment flanges:
- An external drilled flange (12) at the front added on and welded is used for attachment to the air
inlet casing.
- An internal drilled flange (14) at the rear is used for securing the exhaust diffuser.
Figure 1 – Turbine casing
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The cone is drilled with holes at its front on which different bosses are added on and welded:
- At the top, an oblique boss (7) is blanked by a plug (9) fitted with a seal (8).
- On each side, two identical bosses (10) are used for passage and attachment of fuel injectors and
igniters (see chapters 73-10-01 and 74-20-01).
- On the right side, a hole (6) enables borescopic inspection of the combustion chamber and
cleaning of the injection wheel orifices. It is blanked by a cover (4) fitted with a seal (5) and
maintained by six screws (1). This cover comprises a boss blanked by a plug (2) fitted with a seal
(3). This opening on the cover can also serve as air tapping.
- At the bottom, a drilled and tapped boss (11) serves for attaching a purge valve.
Assembly of the rear parts of the engine on the air inlet casing (1) is performed in the three following
sequences:
- The compressor cover (3) is maintained on the turbine casing (4) by three screws (5).
- The counter-casing (2) is assembled with the compressor cover (3) on the turbine casing (4) by
three centering feet (6) fitted with nuts (7).
- The assembly is installed on the air inlet casing (1) and centered using the heads of the centering
foot (6). Assembly is performed by twenty-one screws (8) and three screws (10) which in addition
attach a support (9).
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Figure 2 – Assembly of turbine casing

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4. Purge valve (Figure 3)
A. Description
The purge valve is installed on the drilled boss (1) of the bottom part of the turbine casing. It is
used to evacuate the fuel accumulated in the turbine casing on engine startup or shutdown.
It comprises an upper body (6) on which a lower body (4) is screwed and inside which a blanking
bowl (5) is raised by a spring (3). A seal (2) ensures tightness between the valve and the turbine
casing.
B. Operation
At engine shutdown, the action of the spring enables fuel evacuation through gates cut in the
upper body then through lateral holes drilled in the bowl.
During engine operation, the pressure inside the turbine casing pushes the bowl which blanks the
outlet orifice of the lower body.
This system includes a transient operation which enables expelling the fuel by pressure as long
as it does not exceed the force exerted by the spring i.e. at the beginning of startup or at the end
of shutdown of the engine.
Figure 3 – Purge valve
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C. Pipes (Figure 4)
The purge valve (1) is fitted with a pipe (2) for draining the fuel towards the general draining
orifice of the enclosure.
Figure 4 – Purge valve pipes
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TURBINE CASING
1. Check of purge valve operation
A. Purpose
Purge valve clogging can block it either in the open position or in the closed position.
Blockage in the open position results in a continuous air leak which can cause slight loss of
engine power.
Blockage in closed position cancels the effect of the valve whose function is to evacuate unburnt
excess fuel fallen at the bottom of the turbine casing during engine startup and shutdown. This
excess which is rather important after an aborted startup is often the cause of an excessive rise in
temperature t4 of exhaust gases or even the cause of engine ignition by explosion on the
following startup.
B. Preliminary steps
(1) Remove the left side cover.
C. Procedure (Figure 201)
(1) Unscrew connector (6), remove the drain pipe (7) located in the bottom cover.
(2) During a startup, place the hand near the output orifice of the valve. At the beginning of a
startup, compressed air leakage must be felt which may contain either fuel or fuel vapors.
Then this leakage must disappear during engine acceleration.
The same phenomenon must occur when shutting down the engine but inversely; first, there
is no leak, then leakage occurs towards the end of shutdown.
Any behaviour other than those described above would mean an operation anomaly.
D. Return to operating condition (Figure 201)
(1) Install the drain pipe (7) on the valve, screw in the connector (6) and tighten.
(2) Install the left side cover.
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2. Removal-installation of purge valve (Figure 201)
A. Purpose
- Cleaning of valve.
B. Periodicity
- Periodic inspection at 500 hours of operation.

- In the event of operation anomaly.
C. Means required
(1) Spares
201 2 Seal 72-41 2 7
(2) Possible spares
202 3 Spring 72-41 2 4
202 2 Bowl 72-41 2 5
Figure 201 - Removal-installation of purge valve
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(3) Products
- Solvent (acetone, white spirit, or if not available, fuel).

- Lock wire.
- Graphite grease as per standard AIR 4247.
D. Preliminary step
E. Removal (Figure 201)
(1) Unscrew connector (6), remove drain pipe (7) inside bottom cover.
(2) Unscrew valve (5) by the upper body (3), remove it and discard seal (2).
F. Inspection
(1) Disassembly (Figure 202)
a) Moderately tighten the lower body (4) in a vice.
b) Unlock, unscrew and remove upper body (1).
c) Extract bowl (2) and spring (3) from lower body.
Figure 202 – Cleaning of purge valve
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(2) Checking and cleaning
a) Clean the parts using solvent. Dry them using dry compressed air.
b) Check the spring condition and replace it if necessary.
c) Check the bowl: if it is cracked or broken, replace it.
(3) Assembly (Figure 202)
a) Position the spring (3) and the bowl (2) in the lower body (4).
b) Screw in the upper body (1) on the lower body (4), tighten and lock with lockwire.
c) Remove the valve from the vice.
G. Installation (Figure 201)
(1) Fit the valve with a new seal (2) coated with graphite grease.
(2) Coat the threads of the upper body (3) with graphite grease.
(3) Screw the valve (5) into the corresponding boss of the turbine casing (1), tighten by the
upper body.
- Tightening torque: 1.8 to 2 daN.m
H. Test
(1) Carry out a test as indicated in paragraph 1.
I. Return to operating condition (Figure 201)
(1) Install the drain pipe (7), screw in the connector (6), tighten.
(2) Install the side cover.
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COMBUSTION
COMBUSTION CHAMBER
1. General
The combustion chamber of the ASTAZOU IV M1 is of the annular type. It is designed such that fuel
combustion is complete and takes place under the best conditions to offer maximum efficiency of the
engine.
2. External mixer (Figure 1)
The external mixer comprises two parts: the mixer itself (8) and a swirl plate (6).
Figure 1 – External mixer
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A. Mixer
The mixer consists of a bulging ring fitted with a drilled flange, at the front, for attaching the swirl
plate and a flange fitted with twenty studs (10) screwed into twenty tapped sleeves (9) at the rear,
for attaching the first stage diffuser of the turbine. The sleeves are crimped in the drillings and
maintained by two weld beads.
The ring is drilled with multiple holes for passage (1) of air required for combustion and dilution. A
series of twenty brazed pipes (7) is used for flow or dilution into the combustion chamber.
Two openings (2) are made for passage of injectors and igniters. Borescopic inspection is made
through two additional holes (3) as well as cleaning of the injection wheel.
B. Swirl plate
The swirl plate is secured to the front flange of the external mixer.
It is drilled with multiple oblique holes (4) to create turbulences on air passage. This turbulent air is
required for mixing the fuel.
The central bore has a guide ring (5).
C. Assembly
The external mixer and swirl plate are assembled by twenty-four dowels (11) and nuts (13) fitted
with washers (12). The nuts are tightened then locked by welding.
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3. Internal mixer (Figure 2)
The internal mixer is composed of four distinct parts: a protection Iip (1), a front swirl plate (2), a cone
(5) and an attachment flange (6). The protection lip and the front face form a single piece obtained by
forging. The cone and attachment flange are added and welded.
The protection lip, front swirl plate and cone are drilled with holes (3) of different diameters to create
turbulence on passage of air required for fuel mixing; these are identical to those of the external mixer.
Certain holes are hollow rivets (4) to accentuate turbulence. The flange comprises eight rectangular
openings (8) through which the air supplying the mixer enters.
Eight holes (7) allow for attachment of the mixer with the labyrinth, on the first stage nozzle guide vane
of the turbine.
Figure 2 – Internal mixer
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4. Labyrinth (Figure 3)
The labyrinth surrounds the turbine shaft and is used for cooling it. It ensures tightness of the
combustion chamber.
It is formed of a hollow cylinder (7) whose internal part has two sets of tightness baffles (1) and (5), one
at each end. Between these baffles, two rows of holes (3) are drilled through which the air for cooling
the turbine shaft, flows.
The front baffle lips (1) are machined inside the cylinder whereas the rear baffle lips (5) are added on
and held by a ring (6) welded to the cylinder
The external front part comprises eight bosses (2) on which the internal mixer fits. These bosses allow
for air flow between themselves, towards the mixer protection lip
The rear part includes a drilled flange (4) for attachment to the first stage diffuser.
Figure 3 – Labyrinth
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5. Assembly of combustion chamber (Figure 4)
The external mixer (2) is centered by means of the labyrinth (1) of the centrifugal compressor (see
chapter 72-30-03). It is secured to the external front flange of the first stage nozzle guide vane (5) by
twenty nuts (7) screwed on studs (8). An adjusting washer (6) is inserted between the mixer and the
nozzle guide vane.
The labyrinth (4) engages into the internal mixer (3) protection lip and the assembly is secured to the
internal flange of the first stage nozzle guide vane by eight screws (10) and two tapped segments (9).
The screws are locked by four lock plates (11).
Figure 4 – Assembly of combustion chamber
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6. Air flow (Figure 5)
The compressed air is separated in the combustion chamber into two systems: one combustion system
and one dilution system
The combustion air penetrates mainly through the swirl plate (1) and through the inner mixer (4). It
penetrates the latter after crossing the hollow blades of the first stage nozzle guide vane (6); it also
serves as cooling air for the nozzle guide vane. A part of this air penetrates the rear holes of the
labyrinth (5) and exits through the front to cool the turbine shaft (3).
The dilution air penetrates mainly into the combustion chamber through the external mixer (2) dilution
tubes. The burnt air gas mixture takes place in the rear part of the chamber.
Figure 5 – Air flow
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TURBINES
GENERAL
In the combustion chamber (1), the compressed air-fuel mixture burns and supplies thermal energy in
the form of high pressure hot gases. This energy is recovered and partially transformed into
mechanical energy by a three-stage turbine.
The gases thus enter the turbine through a first stage nozzle guide vane (3) and successively cross
three turbine wheels (4), (6) and (8), separated by two other second stage (5) and third stage (7)
nozzle guide vanes. The turbine wheels have an increasing size so that, at each stage, with the gases
losing their energy progressively, the work load on each wheel is identical. The gases exit through an
exhaust diffuser (9).
The assembly is maintained between a flange shaft (11) and a turbine shaft (2) on which the shaft
nose (15) and injection wheel (14) are secured. Rotation is enabled by a front bearing (16) (see
chapter 72-30-03) and by a rear bearing (10) housed in the exhaust diffuser.
For more security, in addition to the turbine casing (13), a shielding ring (12) surrounds and protects
the turbine.
Figure 1 – Turbines

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TURBINES
SHIELDING
1. General
The shielding provides additional safety for the engine and users.
During engine operation, abnormal operating conditions may result in rupture of the turbine wheel
blades. Due to the high rotation speed, they are projected towards the exterior and can go through the
1st stage nozzle guide vane surrounding them and the turbine casing, or even cause turbine burst.
Turbine shielding is designed to block possible projections of broken blades.
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2. Description of the shielding (Figure 1)
The shielding assembly comprises a shielding ring (1) secured to the turbine casing by two half-shells
(4). Assembly of the ring with the half-shell is obtained by eighteen screws (2) equipped with lock
washers (3) whose locking tabs are folded in the drillings of the ring. Attachment on the turbine casing
is made by means of a drilled flange (5).
Cooling is ensured by air flow through oblong holes (7) and baffles (8) in the ring, and through holes
(6) in the half-shells.
Figure 1 – Shielding
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TURBINES
TURBINE
1. General
The turbine is of the axial type with three integral stages. It consists of two parts, one mobile part
driven in rotation by the pressure of gases supplied by the combustion chamber, and a fixed part
which channels and distributes the gases.
2. Fixed part
A. 1st stage nozzle guide vane (Figure 1)
The 1st stage nozzle guide vane is the main part of the turbine since it not only ensures the
function of gas nozzle guide vane, but also supports the other nozzle guide vanes and the guide
path of the turbine wheels inside which the wheels rotate.
The nozzle guide vane is formed by an outer ring (6) and an inner ring (2). Hollow vanes (1)
welded between these two rings form the 1st stage nozzle guide vane.
Figure 1 – 1st stage nozzle guide vane
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The outer ring is formed by bores with stepped diameters, enlarging towards the rear. In these
bores, the 2nd and 3rd stage nozzle guide vanes are engaged. Two rows of drillings (7), each
with six smooth holes and six tapped holes, are used for securing the 2nd and 3rd stage nozzle
guide vanes. Each end is terminated by a flange:
- a front drilled flange (5) on which the external mixer of the combustion chamber is attached,
- a rear drilled flange (8), on which the turbine casing is attached.
The inner ring comprises a rear drilled flange (4) for attaching the internal mixer and the labyrinth
of the combustion chamber. A second flange (3) is added and welded against the flange (4). The
assembly of these two flanges enables attachment flexibility and a possibility for expansion of the
parts attached thereto.
B. 2nd stage nozzle guide vane (Figure 2)
The 2nd stage nozzle guide vane is formed by two rings separated by a rib (6): one ring (5)
supports the vanes (4) and one ring (7) comprises tightness baffles (8). A band (3) covers the
vanes. It is used for attaching the nozzle guide vane through six drilled holes (2). Notches (1) on
the band are intended to make the band flexible and to avoid rupture due to metal expansion et
high temperatures.
Figure 2 - 2nd stage nozzle guide vane
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C. 3rd stage nozzle guide vane
The 3rd stage nozzle guide vane is identical in shape to the 2nd stage nozzle guide vane. The
only difference is in the size and number of vanes.
3. Mobile part
A. Turbine shaft (Figure 3)
The turbine shaft is made of a hollow cylinder (3) blanked at its rear end.
The front end includes a flange (2) for attaching the shaft nose and the injection wheel. It has a
circular centering rib (1).
The rear face (4) comprises four holes (5) for passage of screws for assembling the mobile
part. A series of twenty-four radial teeth (6) is cut on the external of the rear face. They are
used for connecting the first turbine wheel.
Figure 3 – Turbine shaft
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B. Turbine wheels (Figure 4)
The three turbine wheels are of identical shape; only the dimensions and number of blades vary
from one wheel to the other.
Each wheel is formed of a solid thick disk (2) on which the blades (1) are cut. Each face of the
wheel includes a ring (3) cut with twenty-four teeth (4) for connection with the adjacent part.
Four holes (5) provide for passage of screws for assembling the mobile part.
Figure 4 – Turbine wheel
C. Flange shaft (Figure 5)
The flange shaft is the part which terminates the mobile part and enables attachment of the
latter on the rear bearing of the rotating assembly.
It comprises a shaft (2) fitted with a threading (1) and a mounting flange (3) drilled with four
holes (5) for passage of screws for assembling the mobile part. On the flange, twenty-four
radial teeth (4) are cut for connection with the 3rd turbine wheel.
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Figure 5 - Flange shaft
D. Rotating assembly (Figure 6)
The rotating assembly is formed by assembling the mobile parts of the turbine, the shaft nose and
the injection wheel.
Two centering feet (10) position the shaft nose (11) and the injection wheel (9) on the turbine shaft
(8). The assembly is maintained by six screws (1).
The teeth of the three turbine wheels (4), the turbine shaft (8) and the flange shaft (6) mesh
together and provide the Iink with these parts. Assembly is obtained by four multiple bearing screws
(3) and nuts (5).
Figure 6 - Rotating assembly
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The cylindrical head of these screws comprises a flat used for stopping rotation by bearing on
the turbine shaft separation. A clip (2) in the shaft groove immobilizes the screws during
assembly.
A blanking ring (7) ensures tightness of each gear system.
4. Assembly and operation of turbine (Figure 7)
The rotating assembly, fitted with the centrifugal compressor (2) is assembled on two bearings. The
bearing (1) housed in the compressor casing (12) receives the shaft nose (11) and the bearing
(5) housed in the exhaust diffuser (6) receives the flange shaft (7).
The 2nd and 3rd stage nozzle guide vanes (4) are embedded in the 1st stage nozzle guide vane (3)
and maintained by six positioning pins (14) secured by six screws (13).
The three turbine wheels (10), placed between the 2nd and 3rd stage nozzle guide vane and baffles,
flush the teeth holder rings of the wheels to provide tightness between each turbine stage.
The 1st stage nozzle guide vane is attached with shielding (9) and the exhaust diffuser (6) on the
turbine casing (8) (see chapter 72-50-03).
Figure 7 – Turbine assembly

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TURBINE
1. Check of play in 3rd stage turbine
A. Purpose
(1) Ensure for good condition of turbine and rear bearing.
B. Means required
(1) Set of shims.
(1) Remove the exhaust pipe.
D. Procedure
(1) Ensure there are no traces of friction of turbine blade heads on the nozzle guide vane
casing.
Figure 201 – Measurement of turbine plays
(2) Ensure there are no signs of impact or deformation on the turbine blades.
(3) Using a set of shims, measure the play (J1) between the end of one blade (X) marking it with
chalk, and the casing, at its lowest point.
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(4) Bring the marked blade (X) to the lowest point of the casing and measure play (J2).
The difference between these two measurements must be equal to or less than:
0.30 mm J1 – J2 # 0.30
(1) Install the exhaust pipe.
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TURBINES
DIFFUSER BEARING
1. General
The diffuser bearing comprises an exhaust diffuser in which the rear bearing of the rotating assembly is
installed. The diffuser is used for evacuating gases after their expansion in the turbine.
2. Exhaust diffuser (Figure 1)
The exhaust diffuser has a complex shape and is made of welded elements.
It is composed of a cast star (3) formed by an outer ring and an inner ring, separated by six profiled arms
forming a triangle. A drilled flange (2) is connected to the front of the outer ring by a ferrule (1). An
external shroud (5) fitted with a flange (6) is welded to the rear of the outer ring. The inner ring is fitted
with a bearing cage (11) at the front, and an internal shroud (9) at the rear.
On the external shroud, four drilled and threaded bosses (4) are used for passage and attachment of
control thermocouples (see chapter 77-20-01) and an identification plate.
The internal shroud includes twelve slots (7) and three welded nuts (8) for attaching an outlet cone.
Between these two shrouds, three hollow arms (10) are welded for passage of lubrication pipes.
Figure 1 – Exhaust diffuser

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3. Rear bearing (Figure 2)
The rear bearing of the rotating assembly comprises a body (11) equipped with a cover (1).
A washer (2), a spring washer (5) and an adjustment washer (4) provide a pre-charge to the
bearing (3). The assembly is maintained in a body (11) by an inner stop ring (17). The flange shaft
(19) fitted with a labyrinth ring (18) is held in the bearing (3) by nut (10). The labyrinth ring (18)
ensures tightness by friction in the abrasive-coated bore of the cover (1).
The body and cover comprise flanges by which they are attached with an adjustment washer (6) in
the bearing cage of the exhaust diffuser (15). The assembly is maintained by two sets of three and six
screws (9) and (12) fitted with nuts (16). The screws (9) maintain, in addition, three lubrication pipes (7).
A seal (13) on each pipe and a seal (14) between each flange ensure tightness.
The bearing body (11) is drilled with holes (8) for lubrication and addition of a film of oil around the
bearing (3).
Figure 2 – Rear bearing

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4. Assembly of diffuser bearing (Figure 3)
The exhaust diffuser (10) is attached to the turbine casing (11) with the 1st stage turbine nozzle guide
vane (13), the shielding half-shells (14) and an adjustment washer (12) by means of eighteen
screws (9), the two longer screws of which also maintain a vibration sensor support (8). Six feet (1) are
used to position the nozzle guide vane and diffuser on the turbine.
The three bearing lubrication pipes (7) are formed of a tube fitted with connectors welded at each end.
They cross the hollow arm of the exhaust diffuser and are maintained on a lug (3) secured to the
external connector by a screw (4). These lugs are held against the external front flange of the
diffuser with a reinforcement plate (2) by two of the eighteen screws (9).
An outlet cone (6) is maintained by three screws (5) on the diffuser.
Figure 3 – Diffuser bearing

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DIFFUSER BEARING
1. Crack inspection
CAUTION: IN NO CASE SHOULD THE DIFFUSER BEARING BE REMOVED FROM THE

ENGINE.
A. Purpose
To ensure that the diffuser bearing does not show signs of cracks resulting in harmful operation
and which could cause incidents.
B. Periodicity
No periodicity is required but inspection is recommended during each removal of the exhaust
pipe.
C. Means required
(1) Tools
- Magnifying glass, x 6.
- Metal brush.
(2) Equipment required
- Petrol F or Acetone.
- Dye penetrant product V3 ARDROX 970 P17 9D3/9D4A.
- Abrasive paper.
D. Preliminary steps
Remove the exhaust pipe.
E. Procedure
Clean the areas to be checked.
Spray impregnation liquid on areas to be inspected:
- Wash the areas then dry with hot air.

- Apply developer 9D3/9D4A.
- Using the magnifying glass, inspect the areas to be checked according to acceptance criteria.
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F. Corrective actions
- If the cracks in areas A - B - D - E and F are within tolerances, maintain the engine in
operation.
- If the cracks in areas A - B - D - E and F are out of tolerances or cracks in areas C and G, stop
the engine and inform:
TURBOMECA DTSR TARNOS
for action.
Re-install the exhaust pipe.
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ACCEPTANCE CRITERIA
FRONT FACE OF DIFFUSER (Figure 201)
ANOMALY A:
Crack on leading edge of internal side surfacing.
Acceptable if the length does not exceed 15 mm.
ANOMALY B:
Crack on leading edge of external side surfacing.
ANOMALY C:
Crack on connection of profiled arms with external side shroud.
No crack is acceptable in these areas.
Figure 201 – Front face of diffuser
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REAR FACE (Figure 202)
ANOMALY D:
Crack on trailing edge of internal side surfacing.
ANOMALY E:
Crack on trailing edge of external side surfacing.
Figure 202 – Rear face of diffuser
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EXTERIOR OF DIFFUSER (Figure 203)
ANOMALY F:
Crack starting on trailing edge welding of surfacing.
Acceptable if the length does not exceed 10 mm whatever its orientation.
ANOMALY G:
Crack on boss or separation of thermocouple.
No cracks or separation acceptable.
Figure 203 – Exterior of diffuser
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ACCESSORY DRIVE
GENERAL
Certain accessories of the ASTAZOU IV M1 engine require to be driven in rotation for their
operation. This is carried out directly by the engine.
These accessories are: the starter for igniting the engine, the oil pump for lubrication, and the
governor for maintaining a constant rotation speed.
Driving of these accessories is carried out by a pinion system housed in the oil tank casing, on the
front mounting flange of the air inlet casing and under the reduction gearbox on which the rotation
movement is taken (see chapter 72-10-03).
A relay box transmits the ignition torque of the starter to the engine.
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ACCESSORY DRIVE
PINION SYSTEM
1. General
The accessories are driven by means of a pinion train with the pinions having different diameters to
provide different rotation speeds depending on the accessory driven.
2. General operation (Figure 1)
The general drive is carried out by the shaft pinion (1) of the reduction gearbox (see chapter 72-10-00).
It drives a double pinion (4), which drives a pinion (3) via a pinion (2), and a pinion (6) via a pinion (5).
During the starting phase, movement is initiated by the starter pinion (3) which drives the assembly.
As soon as the starter is cut, the torque is inverted; the assembly is driven by shaft pinion (1) and
pinion (3) rotates as a free wheel. (See 72-60-02).
PINION No. NUMBER OF rpm

TEETH
General drive 1 33 6,360
Intermediate – starter 2 31 3,521
Starter – relay box 3 15 7,276
Oil pump (double pinion) 4 50 and 26 4,198

Intermediate – control unit 5 37 5,673
Control unit 6 53 3,960
NOTE: The rotation speed of the pinions is calculated from a engine shaft speed 43,500 rpm.
Figure 1 – Pinion system
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3. Control unit drive pinion (Figure 2)
The control unit drive pinion is formed by a wheel (1) on which the teeth are cut, and a shaft (6) through
which the pinion is secured in a bearing by a circlip (9).
The bearing consists of two ball bearings (2) separated by a spacer (3) and maintained in a cage (8)
by two circlips (7). The cage comprises a flange (11) for attachment on the air inlet casing (10) by
eight screws (12). Centering is ensured by the cage itself which is countersunk into the air inlet casing.
The hollow shaft has internal grooves (4) and a clip (5) for attaching the drive of the control unit shaft.
Figure 2 – Control unit drive pinion
4. Control unit intermediate pinion
The intermediate pinion provides the movement link between the double pinion and the control unit
drive pinion.
Assembly of this pinion is identical to that of the control unit drive pinion; the only difference between
them is the size and absence of machining in the shaft bore.
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5. Oil pump drive pinion (Figure 3)
The oil pump drive pinion consists of two pinions assembled by welding:
- a pinion (7) receives movement from the shaft pinion and transmits it to the control unit intermediate
pinion,
- a pinion (9) drives the starter intermediate pinion.
The pinion (7) is formed of a wheel cut with teeth, and a hub.
The pinion (9) is formed of a hub on which teeth are cut directly.
The welded assembly forms a hub cage (6) in which a bearing providing rotation is housed.
The bearing comprises two balls bearings (1) separated by a spacer (8) and maintained on a support
shaft (12) by a ring nut (3). The double pinion is secured to this bearing by two circlips (15).
The end of the hub cage comprises four notches for installing a driving unit (5), maintained by a circlip
(2). This driving unit comprises a grooved bore equipped with a clip (4) providing rotation of an oil
pump drive shaft (11), grooved at its both ends.
Figure 3 – Lubrication unit drive pinion
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The support shaft (12) is hollow to allow passage of shaft (11), it includes a flange (14) for attachment
by six screws (10) and its centering on the air inlet casing (13).
6. Starter intermediate pinion (Figure 4)
The intermediate pinion of the starter consists of a cage hub (1) on which teeth are directly cut to form a
pinion. It is mounted on a bearing and is held in place by a circlip (12).
The bearing consists of two ball bearings (3) separated by a spacer (11) and maintained on the
support shaft (10) by a special screw (2). The support shaft comprises a flange (5) with centering base
used for its attachment on the air inlet casing (6) by five screws (4). The end of the screw has a
hexagonal stud receiving a stop (8) equipped with a sealing O-ring (9). This stop, secured to the air
inlet casing by a screw (7), is used to immobilize the screw.
Figure 4 - Starter intermediate pinion
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ACCESSORY DRIVE
RELAY BOX
1. General
The relay box is used to uncouple the start from the engine once the engine is started and operates
independently.
Two ball bearings (5) and (17) provide rotation of a shaft pinion (11) in a cage (1). A free wheel (6),
inserted between the cage and the pinion, carries out occasional connection. The assembly is
installed on two other ball bearings (2) and (12) housed in a unit (3).
The two bearings (12) and (17), separated by a washer (10), are maintained on the pinion by a circlip
(18). Bearing (12) is maintained between a cage (15) and a cover (14) secured on the front of the unit
by five screws (13). This allows immobilization of the pinion. The cage is maintained between bearing
(5) fit on the pinion shaft end and bearing (2) housed in an internal bearing behind the unit, against a
shoulder. The free wheel is positioned between two rings (7) bearing on the outer rings of the bearings
(5) and (17).
Figure 1 – Relay box

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Two of the five screws (13) also maintain a nozzle (9) for lubrication, supplied by a channel drilled in
the unit. A connector (4) provides connection of a supply pipe. An O-ring (8) inserted between the
cage (15) and the cover (14) ensures tightness of the channel.
The unit includes an external flange at the front for attachment of the air inlet housing and a flange at
the rear for securing the starter. An O-ring (16) ensures tightness of the relay box installed on the air
inlet casing.
The shaft pinion (11) meshes with the starter intermediate pinion of the accessory drive pinion train
(see chapter 72-60-01). The splined shaft of the starter engages in the splines of the cage (1).
Switching on the starter causes rotation of the cage and enables, through the free wheel (6), driving
the pinion and consequently the engine. As soon as the engine becomes autonomous, its rotation
speed becomes greater than that of the starter, but the latter is not driven due to the free wheel which,
in this case, no longer connects the pinion and the cage. Thus, the engine can operate without driving
the starter.
4. Assembly of the relay box (Figure 2)
The relay box (2) is secured to the air inlet casing by three screws (1).
Figure 2 – Assembly of the relay box

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RELAY BOX
A. Check attachment and tightness of box.
B. Check condition and attachment of lubrication pipe and tightness of connectors.
C. Check attachment of starter and locking of attachment clamp.
2. Removal-installation of relay box (Figure 201 and Figure 202)
A. Purpose
- Replacement in the event of operating anomaly.
B. Means required
(1) Spares
202 9 O-ring 72-61 2 22
(2) Possible spares
202 7 Seal 72-61 2 27
202 6 Relay box 72-61 2 1
(3) Products
- Vaseline as per standard AIR 3565.
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For all the following operations:

GOGGLES.
(1) Remove the left side and bottom covers (See 71-10-01, pages 200).
(2) Drain the connection casing.
(3) Remove the electric starter.
D. Removal
(1) Unscrew the connectors (4), and remove pipe (5).
(2) Unscrew the three attaching screws (2), and recover the washers (1).
(3) Disengage the relay box (6) from the air inlet housing by pulling parallel to the engine shaft
and remove the box.
NOTE: The pipe and relay box may contain a certain quantity of oil; take necessary
precautions when removing them.
Figure 201 - Removal-installation of relay box
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(4) Extract the O-ring (9) from its housing on the box and discard the ring.
(5) Unscrew the nipple (8), discard the seal (7).
NOTE: This operation should only be carried out if the relay box is replaced.
Figure 202 – Relay box
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E. Installation
(1) Coat the new O-ring (9) with vaseline and position it in its housing on the relay box.
(2) Screw in the connector (8) fitted with a new seal (7) into the corresponding orifice of the box,
tighten.
(3) Insert the relay box in its housing on the air inlet casing, being careful to correctly mesh the
pinion (10) with the engine drive pinion.
(4) Screw in the three screws (2) fitted with their washers (1), tighten.
(5) Install pipe (5), screw in the connectors (4), tighten.
F. Test
(1) Install the starter.
(3) Start the engine and operate it for a few minutes to check for absence of leaks.
(2) Top up the oil tank.
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LUBRICATION
GENERAL
The gears and bearing rollers of the ASTAZOU IV M1 engine require lubrication for their operation.
The high rotation speed of these components requires oil spray lubrication. This type of lubrication
further allows cooling of the parts.
The engine therefore comprises a lubrication system which enables oil storage, flow and treatment. It
includes an oil tank, a lubrication unit, an internal pipe network and an external pipe network.
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GENERAL
SYSTEM OPERATION
1. General
The lubrication system of the engine is a closed system. This means that it distributes the oil and
scavenges it after use, then processes it before using it again.
2. Description - Operation (Figure 1)
A. General operation
The lubrication system of the engine comprises three distinct lubrication areas:
- The first area (3) comprises lubrication of pinions of the reduction gearbox and drive of
accessories and their bearings, front axial compressor bearing, injector connector and torque
limiter bearing.
- The second area (4) comprises lubrication of the axial compressor rear bearing and the
rotating assembly front bearing or centrifugal compressor bearing.
- The third area (5) comprises lubrication of the rotating assembly rear bearing only.
These three areas are served by the same lubrication pump (14) but each area has its own oil
scavenge pump:
- Oil scavenge pump (18) of the reduction gearbox area.

- Oil scavenge pump (17) of the central bearing.
- Oil scavenge pump (16) of the rear bearing.
The oil pump is supplied by a tank (20) and three oil scavenge pumps return the oil, previously
cooled by an oil cooler (1), to this tank. At the outlet of the lubrication pump, the oil passes
through a filter (12) before being injected in the ducts.
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B. Operation and safety accessories
To obtain a consistent flow and pressure of oil, some safety accessories have been added to the
system:
(1) Two check valves (6) and (13) which allow passage of oil only when its pressure is sufficient.
In addition, when the engine is stopped, they prevent oil from being forced back to the oil
pump thus avoiding unpriming of the complete system. The valve (13) is located between the
lubrication pump and the filter, and the valve (6) before the pipes distributing the central
bearing and rear bearing.
(2) A valve (15) short-circuits the lubrication system. If the lubrication oil pressure is greater than
a certain value, the valve opens and allows the oil to return directly to tank through scavenge
pump discharge ducts. The system discharge causes a pressure drop. It is located at the
outlet of the oil pump.
(3) A by-pass (11), installed in parallel with the filter, enables passage of oil in the event of
clogging.
(4) Metallic particles due to wear of gears are stopped by a strainer (19) located before the oil
scavenge pump of the reduction gearbox.
(5) A connector (9) is used for quick connection of instruments, particularly a pressure gauge
which would accurately determine the pressure in the lubrication system.
(6) A STAUBLI connector (23) is used for quick connection of an oil sampling or a pressure
indication pipe.
(7) The system operation is checked by a low pressure switch and a thermal switch probe
assembly (2) (see chapter 79).
(8) Oil vapors in chambers where lubrication takes place are evacuated to the exterior through
ducts.
(9) An intercommunication tube (21) enables oil return from the torque limiter.
(10) A magnetic plug (22) installed on the oil return pipe to tank gives an indication on the
mechanical engine health.
C. Additional lubrication
Pipes (8) and (10) respectively lubricate the relay box and the fuel control unit.

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Figure 1 – Lubrication system
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LUBRICATION SYSTEM
For all interventions on the oil system:

TOXIC. IT CAN BE ABSORBED BY THE SKIN AND PENETRATE IN
THE HUMAN BODY. PROTECT HANDS WITH SYNTHETIC RUBBER
1. Inspection of oil particles
A. Purpose
The analysis of particles and deposits in engine oil provides information on the internal condition
of the engine.
B. Periodicity
- During each periodic inspection of one of the lubrication system filtering elements.
- During each engine draining operation.
- In the event of an anomaly of the lubrication system.
C. Means required
(1) Special tools
- Magnifying glass.
- Magnet.
(2) Products
- Filter paper or clean rag.

- Solvent (acetone, white-spirit, or if not available, fuel).
- Adhesive paper.
D. Procedure
(1) Procedure
a) Filter the scavenged oil, preserve the deposits collected.
b) Clean the parts in contact with the oil using solvent, filter the solvent and also preserve
the deposits collected.
c) Using a magnet, separate the magnetic particles.
d) Using a magnifying glass, if necessary, analyze the particles.
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(2) Analysis of deposits
a) Non magnetic scraps
- Miscellaneous scrap: thread, sand, paint, seal compound, etc. These are normal
and are seen in greater quantities on new engines.
- Carbon dust:
This dust is the result of wearing of a rotating seal and can go up to darkening the
color of oil if there is a great quantity of carbon dust. Remove the engine only if
there is an operating anomaly.
- Rubber scrap:
These can sometimes be identified as parts of O-rings. Rubber can result in
operating anomaly. Confirmation of this anomaly leads to engine removal.
b) Non magnetic metallic particles:
These are accepted in any quantities if not containing magnetic particles.
c) Magnetic particles:
- Unaccountable metal particles in the form of grey or rust colored dust: this dust
results in progressive wear of pinions, grooves, rings and rotating seals. The
presence of this dust is normal. The quantity must not increase considerably
between two inspections. In the event of rapid evolution, simultaneous presence
of an accountable number of particles is observed. Conclusions will be made after
examining the latter.
- Accountable particles rolled over themselves or in the form of a fan: these are
machining chips or detached burrs. The presence of these particles is normal on
new or recently overhauled engines. These chips must disappear after a few tens
of hours of operation.
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- Accountable particles in the form of needles (chips in the form of wires), with a
dark, bluish, grey or mat black color.
This is due to sealing of pinions, grooves, etc. If these needles are in small
number, this is normal. If the number of particles is high, the filter should be
installed after cleaning and another inspection should be carried out after a few
hours of operation. Remove the engine if the quantity of particles is always as high.
Otherwise, keep it in operation and check its evolution.
- Accountable particles in the form of scintillating fine flakes which appear laminated,
with rectangular or round contours:
These particles are due to scaling of bearing parts (balls, rollers, needles,
races). The presence of scintillating fine flakes is not acceptable whatever their
number. Remove the engine.
d) In case of doubt, consult the manufacturer by sending the deposits collected, by buffering
on an adhesive paper. Stick the adhesive paper on a clean paper to trap the deposits.
2. Check of dilution rate
A. Purpose
To detect presence of fuel in lubrication oil.
The presence of fuel in oil can be observed either by characteristic smell of the oil, or by an oil
level increase in the tank, in the event of high dilution.
Dilution can be measured by the flash point method (laboratory) or by the process described below
(practical method).
B. Means required
(1) Special tools
- Ball-type viscosity meter PROLABO 10270-00.

- Oil sampling tool 8810131158.
(2) Products
- New oil, of the same type as that used in the turboshaft engine.
- Fuel, as used in the engine.
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Figure 201 – Ball-type viscosity meter
C. Procedure (Figure 202)
(1) In a first clean recipient, prepare 10 cm3 of the following mixture:
- 1 part of fuel,
- 19 parts of fresh oil (5 % dilution).
(2) In a second recipient, prepare 10 cm3 of the following mixture:
- 1 part of fuel,
- 9 parts of fresh oil (10 % dilution).
(3) Sample approximately 10 cm3 of oil to be examined.
(4) Fill the tubes of the viscosity meter:
- the first tube with a mixture of 5 % fuel,

- the second tube with the oil to be tested,
- the third tube with a mixture of 10 % fuel.
(5) Eliminate air bubbles by filling the tubes completely flush and then placing a plastic seal (3)
pierced with a capillary hole. Then close the tubes with the seal (2) and threaded plug (1).
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(6) Place the tubes on the viscosity meter support (4).
(7) Allow the temperatures to equalize.
(8) Turn over the viscosity meter and compare the times that the balls take to drop to the bottom;
this time is directly proportional to the viscosity of oil.
CAUTION: A DILUTION RATE GREATER THAN 10 % IS UNACCEPTABLE.
NOTE: This instrument can locate the dilution rate between:

0 and 5 % 5 and 10 % More than 10%
Figure 202 – Measurement of dilution rate of fuel in oil
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3. Protection of lubricated areas
A. Purpose
Lubricated areas (rolling parts, bearings, gears, etc.) do not require a mandatorily special
protection; however, in the event of a prolonged shutdown (greater than one week) or before
removal of the turboshaft engine, it is recommended to renew the film of oil protecting these
components.
B. Procedure
This operation is carried out by a simple "VENTILATION" operation for 20 seconds, performed the
first time 24 hours AFTER turboshaft engine shutdown, then once a week.
Also perform a "VENTILATION" operation just BEFORE removal of a turboshaft engine.
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LUBRICATION
OIL TANK CASING
1. General
By its very design, the oil tank casing is an assembly which carries out several distinct and important
functions.
2. Description
A. Perspective view (Figure 1)
The tank casing is formed by a conical circular cavity (3) which, with its closing mounting
flange (1), constitutes the oil tank. This tank is prolonged by a casing (4) with a complex shape
enclosing the reduction gearbox and the accessory drive pinions. A drilled flange (17) terminates
the casing and is used for its attachment to the air inlet casing. A flange (15), encircling the tank,
is used for assembling the connection casing.
The tank is filled from the top through an orifice equipped with a filter (14) and closed by a
plug (13), equipped with a sealing O-ring (8). On each side of this orifice, a spot-faced and
tapped hole receives a connector (16) for connecting the lubrication pipes.
Four see-through plugs (20) are used for checking the oil level in the tank.
Inside the casing, a hollow boss (2) is used for attaching the front bearing of the reduction gearbox
intermediate shaft.
An internal pipe (9), terminated by two attachment flanges, feeds a lubrication nozzle (18). Two
screws (11) and nuts (19) secure one of the flanges and the nozzle on either side of the casing
partition. Two other screws (12) secure the other flange on a channel drilled into the casing
through oil inlet. O-rings (8) ensure tightness.
Each side face of the casing includes a triangular boss (5), which is drilled at its center for
passage of fuel pipes. Another drilled boss (6), on the left face, provides passage and attachment
of the magnetic sensor.
In the casing arm, a duct feeds the lubrication pump. A tube (7), crimped at the inlet to this duct in
the tank, prevents suction of deposits liable to form at the bottom of the tank by oil decantation. A
second duct ensures oil return from the connection casing to the reduction gearbox. A hole, drilled
in the mounting flange, and a socket (10), fitted with O-rings (8), enable connection and tightness.
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Figure 1 – Oil tank casing
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B. Sectional view (Figure 2)
The oil tank casing (1) is secured to the air inlet casing (5) either by screws (2), of different
lengths, fitted with nuts (3), or by screws directly located in the casing. This is done according
to their position and their overall function (support attachment).
A curved boss in the casing arm is fitted with a sheet steel deflector (7), maintained by four
screws (6).
The oil suction pipe (9), which supplies the lubrication pump, is prolonged with another pipe,
drilled in the air inlet housing. A sleeve (8), fitted with an O-ring (4), ensures tightness at the
junction of the two ducts.
The tank is drained through a tapped hole under the tank, blanked by a plug (11), fitted with a
seal (10).
Assembly of the tank casing with the connection casing (14) is obtained by twenty-four screws (12)
and nuts (13).
The closing mounting flange (15) is a disk which is clicked into the tank and is held in place by a
clip (16).
Four drilled holes (17) are used for conveying the oil vapors from the reduction gearbox chamber to
the tank.
Several O-rings (4) ensure tightness of the casing.
Figure 2 – Oil tank casing
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OIL TANK CASING

GOGGLES.
A. Check condition of pipes and tightness of connections.
B. Check closing of filling hole and tightness of blanking plugs. Check their locking.
2. Draining of oil tank casing (Figure 201)
A. Periodicity
- Before sending the engine for overhaul or repair.

- When the fuel dilution rate in oil is greater than 10 %.
- When changing oil.
- When removing the lubrication unit.
B. Means required
(1) Special tools
- Draining tool No. 8811742000 (5).
(2) Products
- Lockwire.
(1) Remove the bottom cover (see Chapter 71-10-01 pages 202 and 203).
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D. Procedure
(1) Unlock and unscrew the cover (2) from the blanking plug (1) under the oil tank
casing (6).
(2) On the blanking plug orifice, install the draining tool (5) and place a recipient (20 litres
minimum) at pipe (4) outlet.
(3) Tighten the knurled nut (3) on the blanking plug; this causes opening of the blanking
plug, oil flow and draining of the oil tank casing.
(4) After all the oil has flowed out, unscrew nut (3), remove the draining tool (5), manually
screw in plug (2) and lock with lockwire.
(1) Install the bottom cover (71-10-01 page 204).
Figure 201 - Draining of oil tank casing
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3. Oil level check
A. Periodicity
- Within the half-hour following shutdown of the turboshaft engine or before starting it up for
operation.
- After an intervention on the oil system of the turboshaft engine (oil cooler, filter, pump, pipes,
etc. ).
B. Procedure
- Carry out one or two ventilation before operation.

- Top up the tank if necessary.
NOTE: For a turboshaft engine which has been shut down since less than half an hour, the
ventilation operations are not required.
CAUTION: WHEN OIL IS HOT, THE OIL LEVEL INDICATION MAY BE ABOVE
THE "MAX." MARK. IN THIS CASE, PARTIAL DRAINING IS NOT
NECESSARY. CHECK LEVEL AGAIN AFTER OIL TEMPERATURE
HAS DROPPED. IF THE LEVEL DOES NOT RETURN TO THE
"MAX." MARK, CARRY OUT A DILUTION RATE TEST FOR FUEL
IN OIL.
4. Filling oil tank casing (Figure 202)
A. Periodicity
- When installing a new or overhauled engine.

- After an oil level check if necessary.
NOTE: 1. The oils used must comply with the specifications of lubrication table in chapter
71-00-03 page 2.
2. If there is doubt or a different oil is used, flush the system (see para. 5 page 205).
B. Means required
(1) Possible spares
202 2 O-ring 72-11 3 3
(2) Products

- Oil.
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C. Procedure (2 cases)
(1) When installing a new or overhauled engine
a) Remove plug (1).
b) Pour fresh oil in the tank up to the "MAX." mark (5).
c) Install plug.
d) Start the turboshaft engine and let it rotate for 3 to 5 minutes.
e) Stop the turboshaft engine and check the oil level. Top up if necessary up to the "MAX."
mark (5).
(2) After checking oil level
a) Remove plug (1).
b) Remove filter (3) and clean using solvent, if necessary.
c) Re-install filter.
d) Pour fresh oil in the tank up to the "MAX." mark (5).
e) Re-install the plug (1) fitted with a new seal (2), if necessary.
Figure 202 - Filling the oil tank casing
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5. Rinsing oil system or changing from one synthetic oil to another with a different brand or different
specification or in the event of pollution in system
A. Completely drain the oil system (tank – oil cooler).
B. Drain the oil filter.
C. Fill the tank up to the "MIN." mark (first lower indicator) with oil corresponding to the brand or
specification required.
D. Carry out a ground run check for a minimum of 5 minutes at an oil temperature of 40 °C minimum.
E. Drain the oil system and the fiIter.
CAUTION: IF RINSING IS PERFORMED DUE TO OBSERVATION OF

PARTICLES IN THE OIL SYSTEM, REPLACE THE OIL FILTER
AND CLEAN THE OIL TANK CAREFULLY.
IF THE OIL FILTER WAS CLOGGED, THE OIL COOLER MUST
ALSO BE REPLACED.
F. Fill the tank with the desired oil.
NOTE: 1. During factory tests, the turboshaft engines are lubricated with oil 0-150.
2. When replacing a hydraulic equipment (oil pump or speed governor) on an engine

using a different synthetic oil, the engine need not be rinsed as described above.
The quantity of residual oil in the equipment is low with respect to that in the
engine. There, the equipment may simply be drained before installing the engine.
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LUBRICATION
LUBRICATION UNIT
1. General
The four pumps used for operation of the oil system are combined into a single block designed to be
driven with a single drive, for all four pumps at the same time. With the filter, this block constitutes the
engine lubrication unit.
2. Oil pump
A. One pump (Figure 1)
The four pumps are of the gear-driven type. Each comprises a driving pinion (2), driven by a drive
shaft (1) using a pin (3). This pinion meshes with a driven pinion (10) installed free on the driven
shaft (11). The drive and driven shafts are common to the four pumps.
These gears are housed in four pump bodies (9) separated by three mounting flanges (5), which
comprise bores fitted with crimped sleeves (6) and form the bearings of the shafts. Openings (4)
and (12) and drilled holes (7) and (8) provide passage and distribution of oil to the pumps.
Figure 1 – One pump
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B. Pump unit (Figure 2)
The pump unit is the result of the assembly formed by the four pumps between a base (1) and a
cover (7), in a bushing (6), secured by three screws (17) and two centering rods (5).
Two O-rings (2) ensure tightness.
The drive shaft (4) includes inner splines and a clip (18) for receiving the drive shaft of the
accessory drive pinion lubrication unit (see chapter 72-60-01). Tightness of the shaft passage
opening in the base is by means of a lip seal (19).
One of the driven pinions, with a pin (14), drives the driven shaft (12) and a shaft (11) housed
internally. This shaft crosses the cover. A lip seal (9) ensures tightness of the opening. One end
of the driven shaft comprises an O-ring (13) and the other, guided by a ring (10), includes a
hollow square for driving, if necessary, a tachometer. The tachometer is not used on the
ASTAZOU IV Ml.
A plate (3) has two lip seals (16) ensuring tightness at shaft level, between the lubrication pump
and the three oil scavenge pumps. Two seal pellets (15) ensure the same function inside the
shafts. Two clips (8) limit axial movement of the two shafts.
Figure 2 – Pump unit
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3. Oil filter (Figure 3)
The oil filter is mounted on the base (1) of the oil pump. It comprises a filtering element (3) and a cover
(4), held in place by a screw (7), screwed into a sleeve (14), itself screwed into the base.
A bush (8), crimped into the cover, guides the upper part of the filtering element. The lower part, fitted
with a seal (12) engages in a seating sleeve, (13), crimped in the base. A spring (5) bears on a circlip
(9) to maintain the filtering element against the seating sleeve, by means of a seal holder (11) cup
(10). Seals (11) and (12) ensure tightness at the level of the filtering element, between the filtered and
non-filtered oil. An O-ring (2) ensures tightness of the cover on the base, and a seal (6) that of the
cover on the screw.
Figure 3 – Oil filter
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4. Operating and safety accessories
Some of the operating and safety accessories are built into the lubrication unit.
A. Pressure relief valve (Figure 4)
The pressure relief valve is housed in one of the scavenge pump bodies (5).
A valve (2) pressed against a spring (3) closes a channel (1) coming from the lubrication pump
outlet. An overpressure pushes the valve, returning the oil to the tank through the discharge
channel (4) of the scavenge pumps.
Figure 4 – Pressure relief valve
B. Strainer (Figure 5)
The strainer is formed by a filtering cone (7) brazed on a sleeve (4), drilled longitudinally and
transversely.
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The oil comes in from the reduction gearbox through a hole (8) drilled into the rear face of the
base (1), passes through drilled holes in the sleeve, crosses the filtering cone and is sucked in by
the scavenge pump, through channel (6).
The sleeve, fitted with an O-ring (9), is secured to the base by a screw (5).
C. Check valve (Figure 5)
The first check valve, located between the lubrication pump and the oil filter, is housed in the
base (1).
It comprises a ball (13), guided in a valve body (3) and pressed, by a spring (16), against the
orifice of a seating sleeve (11). The seating sleeve is fitted with an O-ring (12) and crimped at the
end of channel (10) coming from the lubrication pump. Under the effect of pressure from the
lubrication pump, the ball moves, thus allowing the oil to pass through a notch in the valve body,
located in front of the channel (14) leading to the filter. The valve body, fitted with an O-ring (15),
is secured to the base by a screw (2).
Figure 5 – Strainer and check valve
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D. By-pass (Figure 6)
The by-pass is located in the base (1) below the oil filter.
Before crossing the filtering element (6), the oil comes into a circular cavity (5) and goes out,
filtered, through channel (7).
The by-pass comprises a valve (3) maintained by a spring (2) against a circlip (4), in a hole drilled
between the circular cavity and the channel (7). This valve blocks the hole. When the filter is
clogged, the pressure in the circular cavity increases. This pressure is exerted on the valve which
moves and allows the oil through directly into channel (7), by-passing the filter.
Figure 6 – By-pass

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E. Magnetic plug (Figure 7)
The magnetic plug (3), of the self-blanking type, is installed on a plug holder (2), outside the
coverings of the oil return system (1).
It is used to make a rapid and frequent check of the internal condition of the engine, without
having to remove the oil filter.
Figure 7 – Magnetic plug

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5. Oil flow in lubrication unit (Figure 8)
A. Lubrication unit
The lubrication pump (4) sucks in oil from the tank through a channel (6), which starts at the rear
face of the base (2). Then, the pump discharges this oil into the circular cavity (12) of the oil filter,
via the check valve (10) in the base. The oil surrounds the filtering element (13), penetrates inside
and returns to the base in which it is divided into three networks.
- A channel (3) leading to the rear face of the base, feeds the reduction gearbox.
- A channel (11) leading to the side of the base, feeds the FCU and the low pressure switch.
- A channel (9) also leading to the side of the base, supplies the central bearing, the rear
bearing and the relay box.
The by-pass (8) directly supplies these three networks from the circular cavity, in the event of the
filter (13) clogging. The oil pressure is controlled by the pressure relief valve (15) which evacuates
the excess flow towards the discharge (20) of the scavenge pumps.
B. Scavenge pumps
The three scavenge pumps discharge oil through a common channel (20), which leads to the side
of the cover (8).
The scavenge pump of the reduction gearbox (5) sucks in oil through a channel (7), fitted with the
strainer (1). This channel starts on the rear face of the base.
The scavenge pumps of the central bearing (14) and rear bearing (16) suck in oil, respectively
through channels (19) and (17) which start on the front face and on the side of the cover.

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Figure 8 – Oil flow

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6. Lubrication unit equipment (Figure 9)
The lubrication unit includes equipment items for adapting the unit to the engine.
A. Equipment for lubrication orifices
Certain lubrication orifices are fitted with components for connecting lubrication pipes:
- A connection flange (2) is secured, by two screws (3) and a screw (4), to the oil suction
orifice of the rear bearing. It is fitted with a straight connector (6) and an angle connector (7).
- A connection flange (14) is secured, by two screws (15) to the lubrication orifice of the
central bearing, rear bearing and relay box. It receives the following, screwed respectively
one against the other: a straight connector (6), a T-connector (13), a second straight
connector (6), a non-return valve (12) and a nipple (10).
- A double flange (17) is secured, by two screws (18), to the lubrication orifice of the fuel
control unit. On one side, it is fitted with a nipple (10) and on the other, with a quick
connector (16).
- The lubrication orifice of the reduction gearbox receives a sleeve (20).
- Tightness is ensured by several seals (5) and O-rings (1), some of which are maintained in
retaining rings (11).
B. Other equipment
The bore intended to connect a tachometer is blanked by a plate (9) maintained by four
screws (8).
The base comprises a circular groove on the rear face in which an O-ring (19) ensures tightness
of the unit secured to the engine.
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Figure 9 – Equipment
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7. Attachment of lubrication unit (Figure 10)
The lubrication unit (3) is secured to the air inlet casing (2) by three screws (1).
During assembly, the lubrication orifices of the rear face of the base communicate directly with the
lubrication channels drilled into the air inlet housing. The sleeves fitted with their O-rings ensure
tightness at the junction points of the channels.
Figure 10 – Attachment of lubrication unit
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LUBRICATION UNIT

GOGGLES.
A. Check attachment of unit.
B. Check for absence of oil leaks at different mating faces, at filter cover, at the strainer and at the
check valve.
C. Check condition of pipe attachments and tightness of connectors.
D. Check for absence of oil leaks as well as locking of the magnetic plug.
2. Removal-installation of oil filter (Figure 201)
A. Purpose
- Cleaning or replacement of filtering cartridge.

- Examination of lubrication system by oil filter analysis.
B. Periodicity
- Cleaning of filtering cartridge every 250 hours of operation.

- Replacement of filtering cartridge every 500 hours of operation.
- In the event of operation anomaly of the lubrication system.
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C. Means required
(1) Systematic spares
201 2 O-ring 72-81 3 12
201 3 O-ring 72-81 3 11M
(2) Possible spares
201 4 Filter 72-81 3 11
201 7 Seal 72-81 3 3
201 10 Seal 72-81 3 10
(3) Products
- Vaseline, as per standard AIR 3565.

- Lockwire.
(1) Remove the left side cover and the bottom cover.
(2) Place a recipient below the lubrication unit to recover oil contained in the filter.
E. Removal
(1) Unlock and loosen screws (6).
(2) Slightly clear aside the cover (5) of the base (1) and allow oil to flow in the recipient.
(3) Disengage the filtering cartridge (4) from the base and simultaneously remove the screws,
cover and cartridge.
(4) From their recess, extract the O-ring (2) and the O-ring (3) of the filtering cartridge, if it has
remained on the base; discard the seals.
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(5) Separate the filtering cartridge from the cover and remove seal (10), cup (9) and spring (8);
discard seal (10).
(6) Take out O-ring (3) from the filtering cartridge if the seal has remained on it.
(7) Remove screw (6) from cover, discard the seal (7).
Figure 201 – Removal-installation of oil filter
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F. Check
(1) Carry out an analysis of the oil collected.
(2) Check the condition of the filtering cartridge:
a) After cleaning the cartridge, dry it using dry compressed air, by blowing from inside to
outside.
b) Carefully examine the condition of the cartridge; replace it if necessary.
c) Systematically replace the cartridge according to the periodic inspection tables (see
chapter 05-10-02).
G. Installation
(1) Dry all components with a blast of dry compressed air.
(2) Install a new O-ring (2) coated with vaseline into its recess in the base (1).
(3) Install a new O-ring (3) coated with vaseline on the filtering cartridge (4), if the latter was
recovered.
(4) Insert screw (6), equipped with a new seal (7) into the cover (5); on the screw, slide the
spring cover (8), the cup (9) and a new seal (10).
(5) Insert the filtering cartridge (4) in the cover, on the screw.
(6) Install the assembly on the cover (1), screwing the screw (6) and tightening by hand. Lock
with lockwire.
H. Test
(2) Start up the engine and operate it for a few minutes to check for absence of leakage on the
filter.
I. Return to operating condition
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3. Removal-installation of the strainer (Figure 202)
A. Purpose
- Cleaning and inspection of deposits retained in strainer.
B. Periodicity
- During periodic inspection every 250 hours of operation.

- In the event of operation anomaly of the lubrication system.
C. Means required
(1) Spares
202 3 O-ring 72-81 3 18
(2) Possible spares
202 2 Strainer 72-81 3 16
(3) Product
- Vaseline, as per standard AIR 3565.
(3) Place a recipient below the lubrication base to recover remaining oil.
E. Removal
(1) Loosen screw (1).
(2) Disengage the strainer (2), leave the oil to flow out then remove it.
(3) Remove the O-ring (3) from its recess on the strainer and discard it.
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F. Check
(1) Carry out strainer oil analysis.
(2) Check condition of strainer.
a) After cleaning, dry with dry compressed air.
b) Carefully examine the condition of the strainer and replace it if required.
G. Installation
(1) Install a new O-ring (3) coated with vaseline, in its recess on the strainer (2).
(2) Insert the strainer on the base (4) of the lubrication unit, install and screw in screw (1);
tighten.
H. Test
(1) Install bottom cover.
(2) Start up the engine and operate it for a few minutes to check for absence of leakage from the
strainer.
I. Return to operating condition
(2) Top up the tank with oil.
Figure 202 – Removal-installation of the strainer
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4. Removal-installation of the lubrication unit
A. Purpose
- Replacement of the drive shaft or of the unit in the event of operating anomaly.
B. Means required
(1) Spares
204 5 2 O-rings 72-21 2 34

204 11 O-ring 72-21 2 32
205 14 O-ring 72-81 2 20
205 15 O-ring 72-81 2 25
205 12 2 O-rings 72-81 2 33
205 4 O-ring 72-81 1 8
205 8 O-ring 72-81 3 37
205 9 O-ring 72-81 3 44
(2) Possible spares
205 13 Splined shaft 72-61 1 5
205 5 Lubrication unit 72-81 1 9
(3) Products

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(2) Drain the oil tank casing and the connection casing.
(3) Remove the fire detector (10) (Figure 203).
(4) Place a recipient below the lubrication unit to recover the remaining oil.
D. Removal
(1) Removal of pipes (Figure 203).
NOTE: These pipes can contain some oil; take all necessary precautions when removing
them.
a) Unscrew connectors (5), (6), (9) and (12) and remove pipes (4), (7), (8) and (13).
b) Unscrew the attaching clamp screw (3), recover the washer, separate the two collar
attachment lugs (1) and remove these parts.
c) Unscrew connector (2) and the two screws (11). Remove the pipe (14) and discard the
O-ring (15).
Figure 203 – Removal of pipes
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(2) Removal of unit (Figure 204)
a) Unscrew the two screws (7), recover their washers and remove the fire detector
attachment support (5).
b) Unscrew the two screws (8), recover their washers and remove the blanking plate (4).
c) Unscrew the two screws (9), recover their washers and simultaneously remove the seal
connector (10) and the connector tube (1).
d) Remove the O-rings (11) and (2) from their housing on the connector and tube. Discard
the O-rings.
e) Unscrew the three attachment screws (3), disengage the unit from the air inlet casing,
allow the oil to flow out and remove the unit (6).
Figure 204 – Removal of lubrication unit
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(3) Removal of unit components (Figure 205)
a) Remove the splined shaft (13) from the lubrication unit or the air inlet casing according
to whether the shaft has remained on one or the other part.
b) Remove the O-ring (14) from its housing on the unit; discard the O-ring.
c) Remove seals (15) and (12) from the connection sleeves on which they are placed;
discard the seals.
d) Unscrew screws (1) and (2), remove the connection flange (3) and discard O-ring (4).
e) Unscrew the two screws (6), remove the connection flange (7) and discard the O-ring
(8).
f) Unscrew the two screws (11), remove the double flange (10) and discard the O-ring (9).
NOTE: Flanges (3), (7) and (10) are removed along with the components secured
on them.
Figure 205 – Removal of lubrication unit components
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E. Check
(1) Carefully examine the condition of the splined drive shaft of the unit; discard it, if it is found to
be the cause of the operating anomaly; otherwise, replace the lubrication unit.
F. Installation
(1) Preparation
a) Clean the components with solvent and dry with dry compressed air.
(2) Equipment of unit (Figure 205)
a) Install the connection flanges (3) and (7) and the double flange (10), fitted with new
O-rings (4), (8) and (9) coated with vaseline. Screw in screws (1) and (6) fitted with their
washers, and screws (2) and (11). Tighten.
b) Install a new O-ring (14) coated with vaseline, in its housing on the unit.
c) Fit new O-rings (12) and (15), coated with vaseline, on the connection sleeves of the
unit and air inlet casing.
d) Insert the splined drive shaft (13) into its hole on the air inlet casing.
(3) Installation of unit (Figure 204)
a) Coat the threads of the three screws (3) with engine oil, and insert them in the unit.
b) Install the unit on the air inlet housing, by positioning the drive shaft passage hole
opposite the air inlet housing. Engage the unit in the air inlet housing, taking care in
correctly engaging the drive shaft into the unit, position the unit by engaging the
connection sleeves into their respective hole, screw in screws (3) and tighten.
c) Install two new O-rings (2), coated with vaseline, on tube (1).
d) Install a new O-ring (11) in its housing on connector (10).
e) Fit the tube into the connector, then the other end into the unit cover, in the
corresponding hole. Install screws (9) fitted with their washers, screw in and tighten.
f) Install blanking plate (4), maintain it by two screws (8) fitted with their washers, do not
tighten. Install the fire detector support (5), screw in two screws (7) with their washers.
Tighten four screws (7) and (8).
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(4) Installation of pipes (Figure 203)
a) Install pipe (14) fitted with a new O-ring (15), coated with vaseline, screw in two screws
(11) and connector (2). Install the two clamp lugs (1) on the support bracket, screw in
screw (3) and tighten.
b) Install pipes (4), (7), (8) and (13), screw connectors (5), (6), (9) and (12) and tighten.
G. Test
(1) Install the fire detector (10) (Figure 203).
(2) Fill the tank with oil.
(4) Start up the engine and operate it for a few minutes to check for absence of leakage.
H. Return to operating condition
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5. Removal of magnetic plug (Figure 206)
A. Purpose
Inspection of the engine internal health.
B. Periodicity
- According to engine inspection periodicities.

- In the event of operating anomalies.
- When particles are observed in filter.
C. Means required
(1) Spares
206 2 O-rings 72-81 3M 3
(2) Special tools
- Magnifying glass x 6.
- Magnet.
(3) Products
- Solvent (trichlorethane - chlorotene or other degreasing products).

- Adhesive paper.
Place a small recovery pan below the magnetic plug (1).
E. Removal
- Remove plug (7) by pressing and turning it counterclockwise to unlock it.

- Remove and discard the two O-rings (2).
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F. Inspection of plug
(1) Particle recovery method
- Soak the plug (1) in solvent to degrease it (do not use metallic recipient).
- Leave it in the open air to allow evaporation of the product.
- Insert adhesive paper between the plug and the magnet to collect particles.
(2) Particle analysis
Analyze the particles according to the maintenance operations described in chapter 72-80-
01.
(3) Decision criteria
a) If the number of dark needles is greater than 10, proceed as follows:
- Re-install plug (1) fitted with seals (2).

- Carry out a ground run check and re-examine the plug.
- If the particles are still as many, remove the engine.
b) No scintillating particle is accepted. Remove the engine.
G. Installation
- Install two seals (2) then install plug (1).

- Pull on the plug to ensure that it does not turn in any direction.
Figure 206 – Removal-installation of magnetic plug
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LUBRICATION
INTERNAL DUCTS
1. General
The engine comprises pipes and drillings on certain parts of the structure used for oil discharge
towards specific points where lubrication takes place.
2. Lubrication of reduction gearbox area
A. Lubrication of bottom part (Figure 1)
The lubrication system of the reduction gearbox area is supplied directly through the base of the
lubrication unit (15) through drilling (1). The oil penetrates into the cavity (2) then into tube (6).
This tube is prolonged by drillings (9) made in the tank casing for lubricating the roller bearing
(10) and supplying the nozzle (7) via internal duct (8). This nozzle lubricates the pinion meshing
of the output wheel intermediate assembly (5).
Figure 1 – Lubrication of bottom part of reduction gearbox
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Lubrication of the roller bearings (11) and ball bearings (12) is obtained through a series of
drillings made in the tube (6), the pinion shaft (4), the intermediate pinion assembly (5) and the
bearings themselves.
Deflector (13) prevents oil emulsion caused by the intermediate wheel. Lubrication of the
accessory drive pinions (14) and their bearings is carried out by splash lubrication. A drilling (3)
channels the oil towards the top parts.
B. Lubrication of top part (Figure 2)
The oil arrives in the top part into the circular cavity (2) formed by the hub casing in which two
lubrication systems are formed by two series of drillings (13) and (3).
Drillings (13) supply nozzle (14) which sprays oil on the roller bearing (12). This nozzle is
prolonged by drillings made in the hub (15) which ensure the supply for lubricating the front
bearing (16) of the axial compressor.
The drillings (3) firstly provide lubrication of the roller bearings (7) through the washer (5) and
secondly, supply a circular cavity (6) formed by the oil distributor (4) in which a series of drillings
provide lubrication of the ball bearings (10) and roller bearings (11) and of the coupling sleeve
splines (1).
Figure 2 – Lubrication of top part of reduction gearbox
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The cavity (6) also supplies two other systems. The nozzle (18), supplied by drilling (17),
lubricates the intermediate wheel pinion meshing (19) and the oil is injected on Sealol seal (9)
and towards the torque limiter by a series of drillings (8) made in the injector connector body.
C. Lubrication of torque limiter (Figure 3)
Lubrication of the torque limiter takes place by oil projection through drilling (5) of the injector
connector body.
A jet penetrates the hub (1) of the torque limiter. This oil is driven by centrifugal action through
radial drillings (3) made in the hub, towards friction disks (2) for their lubrication.
A second jet lubricates the sleeve guide (4) and the coupling splines with the outlet wheel.
Figure 3 - Lubrication of torque limiter
D. Evacuation and venting
Various machinings and drillings allow oil evacuation after lubrication towards the reduction
gearbox casing bottom where it is recovered by the scavenge pump. OiI vapor evacuation
towards the tank and venting of the reduction gearbox take place through drillings (6).
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3. Lubrication of central bearing (Figure 4)
The three profiled arms of the compressor casing (3) are used by the lubrication system to reach the
central bearing area.
The first arm is used, through drillings (4) followed by drillings (5) in the cover cage, to supply the rear
bearing (1) of the axial compressor, for its own lubrication. From the cover cage, the tube (5) drives a
part of the oil towards the circular cavity (7) formed by special nut (10) in the cage (6). In these two
parts, drillings allow lubrication of the ball bearing (8), of the Sealol seal (9), of the cage centering
bosses and of the drive sleeve splines (11).
By gravitation, after lubrication, the oil falls to the bottom of the internal cone of the compressor casing,
where it is recovered by duct (12) drilled in the second arm.
Channel (13) of the third arm evacuates oil vapors.
Figure 4 – Lubrication of central bearing
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4. Lubrication of rear bearing (Figure 5)
The rear bearing is lubricated by three hollow arms of the exhaust diffuser.
The oil is channelled through tube (4) then through drillings (3) and is projected on the ball bearing (1)
through tube (2). After lubrication, the oil is evacuated through millings and drillings (5), and recovered
through tube (6). The oil vapors infiltrate the lips of labyrinth ring (9) and are expelled towards the
evacuation tube (7) through drillings (8).
Figure 5 – Lubrication of rear bearing
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5. Lubrication of relay box (Figure 6)
The lubrication oil is introduced in the relay box through nipple (3). The drilling (5) in the box channels
this oil towards the nozzle (6) in which drillings, on one hand, lubricate the ball bearing (9) and, on the
other hand, project oil onto the shaft pinion (8). By centrifugal action, the drillings in this pinion
lubricate the free wheel (4), the ball bearing (2) and the ball bearing (11) through washer (7). The
lubrication oil crosses the ball bearing (2) and is conveyed to the ball bearing (1) for lubrication.
Figure 6 – Lubrication of relay box
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Drillings in some of the parts allow for oil flow after lubrication towards the bottom of the box where
other drillings enable its evacuation towards the tank casing. Identical drillings (10) in the top of the
box allow for oil vapor evacuation.
6. Lubrication of fuel control unit
See Chapter 73-30-01.
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LUBRICATION
PIPES
1. General
The engine is fitted with modelled metal pipes for driving oil into the lubrication unit and into the areas
where lubrication takes place. Other pipes evacuate oil vapors towards the outside of the engine.
2. Internal pipes
Since lubrication of the central bearing takes place through channels drilled in the compressor casing,
a set of pipes is used to supply these holes from the exterior of the air inlet casing.
A. Pipes (Figure 1)
Three holes in the compressor casing arm (3) are connected to a drilled strip (6) secured on the
sleeves of the counter-casing (2) by two screws (7).
Figure 1 – Internal pipes
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Two pipes (5) and (10) connect the upper lubrication and venting holes. They comprise tubes
fitted with a brazed mounting flange at each end. They are secured to these flanges (1) by five
screws (4) on the compressor casing and on the strip.
The lower hole for oil scavenge is fitted with a connector (9) and secured to the compressor
casing by two screws (4). A tube (8) is used to connect the strip by engaging in the two parts.
Several O-rings (1) ensure tightness.
B. Connection assembly (Figure 2)
The three lubrication systems, connected to the strip (2), are connected to a connection unit (6)
by three tubes (1). The connection unit is secured in the bottom bulge of the air inlet casing (3) by
two screws (4). The tubes, equipped with O-rings (5) are maintained fit between the connection
strip and the connection unit, crossing the partition of the air inlet casing.
Figure 2 – Connection assembly
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C. Equipment of connection unit (Figure 3)
The three holes of the connection unit (10) are equipped with components for attaching the
supply pipes.
The lubrication hole receives a nipple (1) fitted with a seal (2).
The oil vapor scavenge hole receives a straight connector (3), fitted with a seal (2), and an angle
connector (4).
A connection flange (6), fitted with an O-ring (5), is secured to the oil scavenge hole by two
screws (7). A tube (8), fitted with two O-rings (5), enables oil flow between this connector and the
cover (9) of the lubrication unit. It is maintained fit between these two parts.
Figure 3 – Equipment of connection unit
D. Other internal pipes
The engine also comprises an internal pipe (described in chapter 72-80-02) and three rear
bearing lubrication pipes (described in chapter 72-80-04 page 5).

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3. External pipes (Figure 4)
A. Lubrication pipes
The engine lubrication pipes start from the base of the lubrication unit. They are connected to the
components of two lubrication holes:
- The first hole receives a pipe (1), for supplying the relay box, and a pipe (3), connected with
a T-connector (4), on which are connected a pipe (5) for feeding the rear bearing, and a
pipe (7), connected to the connection unit, supplies the central bearing.
- A pipe (9) connects the second lubrication hole to a T-connector (8), secured on the control
unit, from which starts pipe (33) supplying the low pressure switch.
- A pipe (32) connects the load pressure switch to the fuel control unit.
B. Oil scavenge pipes
- A pipe (6) connected to the cover of the unit is used for oil return from the rear bearing.
- A pipe (10) enables discharge of scavenge oil from the pumps. It comprises a flange fitted
with an O-ring. It is attached to the cover of the unit by two screws (11). It is also maintained
by a clamp (13), secured by a screw (14) on a bracket (12) itself maintained by one of the oil
tank casing attachment screws on the air inlet casing. A nipple (16) enables connection of
this pipe to a following pipe (15) which, through at set of components, is connected to a third
pipe (25), connected to the oil cooler inlet. This set comprises a nipple (20) secured to the
front frame of the covering by a nut (19).
An angle connector (18) is used for connecting pipe (15). A connector (22) screwed onto the
second hole receives the magnetic plug holder (24), on which pipe (27) is connected through
connector (26).
- On the oil cooler outlet, a pipe (30) is connected, which ensures oil return to the tank, with a
pipe (29) connected on the latter. The link between these two pipes is made by means of the
probe-thermal switch assembly (31), on which these are connected.
NOTE: For installation of pipes (27) and (30), refer to chapter 79-10-01 pages 200.

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Figure 4 – External pipes

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C. Venting pipes
- The venting hole in the oil tank casing receives a pipe (28) which is connected to another
pipe (17) through a second set of components secured to the front frame, comprising a
nipple (20), maintained by a screw (19) and fitted with two angle connectors (18) and (21).
- A pipe (2), connected to the connection unit, ensures transfer of oil vapors from the central
bearing to the oil tank casing, where they are vented.
- A pipe (34) is used for venting from the rear bearing.
NOTE: Pipes connected to the rear bearing are connected to pipes described in
chapter 72-50-03.

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FUEL SYSTEM
TABLE OF CONTENTS
General
- Authorized fuel 73-00-01 1

- Fuel system 73-00-02 1 to 3
Maintenance operations 201
Ignition system
- Injectors 73-10-01 1 to 3
Startup system
- Startup units 73-20-01 1 to 9

Main system
- Fuel control unit 73-30-01 1 to 28

Fuel system equipment
- Internal parts 73-40-01 1 to 5

- Solenoid valves 73-40-02 1 to 5
- Accessories 73-40-03 1
- Pipes 73-40-04 1 to 3

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FUEL SYSTEM
73 1 Sept. 1991 73-30-01 1 May 1981

2 Sept. 1995 2 May 1981
3 Sept. 1995 3 May 1981
4 May 1981
72-00-01 1 Dec. 1983 5 May 1981
6 May 1981
73-00-02 1 May 1981 7 May 1981
2 May 1981 8 May 1981
3 Dec. 1983 9 May 1981
10 May 1981
201 Sept. 1995 11 Sept. 1991
12 May 1981
73-10-01 1 Dec. 1983 13 Dec. 1983
2 May 1981 14 May 1981
3 May 1981 15 May 1981
16 May 1981
201 May 1981 17 Dec. 1983
202 May 1981 18 May 1981
203 May 1981 19 May 1981
204 Dec. 1983 20 May 1981
205 May 1981 21 May 1981
206 May 1981 22 Dec. 1983
207 May 1981 23 Dec. 1983
24 Dec. 1983
73-20-01 1 May 1981 25 May 1981
2 Dec. 1983 26 May 1981
3 Sept. 1991 27 May 1981
4 May 1981 28 May 1981
5 Dec. 1983
6 Sept. 1991 201 Sept. 1991
7 May 1981 202 Sept. 1991
8 May 1981 203 Sept. 1991
9 May 1981 204 Sept. 1991
205 Sept. 1991
201 May 1981 206 Sept. 1991
202 May 1981 207 Sept. 1991
203 May 1981 208 Sept. 1991
204 May 1981 209 Sept. 1991
210 Sept. 1991
211 Sept. 1991
212 Sept. 1991
213 Sept. 1991
214 Sept. 1991
215 Sept. 1991
216 Sept. 1991

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73-40-01 1 Sept. 1991

2 June 1994
3 May 1981
4 May 1981
5 Sept. 1991
201 Sept. 1991

202 Sept. 1991
203 Sept. 1991
204 Sept. 1991
205 Sept. 1991
206 Sept. 1991
207 Sept. 1995
208 Sept. 1995
73-40-02 1 Dec. 1983

2 Sept. 1991
3 Sept. 1991
4 Sept. 1991
5 Sept. 1991
201 Sept. 1991

202 Sept. 1991
203 Sept. 1991
204 Sept. 1991
205 Sept. 1991
206 Sept. 1991
207 Sept. 1991
208 Sept. 1991
209 Sept. 1991
210 Sept. 1991
211 Sept. 1991
212 Sept. 1995
213 Sept. 1991
214 Sept. 1991
215 Sept. 1991
216 Sept. 1991
73-40-03 1 May 1981
73-40-04 1 May 1981

2 Sept. 1995
3 Dec. 1983
201 May 1981

202 May 1981
203 May 1981

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GENERAL
AUTHORIZED FUEL
Specification
See Chapter 71-00-03 Page 1
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GENERAL
DESCRIPTION OF SYSTEM
1. General
The fuel system is broken down into three systems each corresponding to an engine operation phase.
These systems are not entirely independent with respect to each other but each system comprises
components which are specific for its operation.
2. Breakdown of fuel system
A. lgnition system
This system is used to ignite the combustion chamber, by igniting the fuel sprayed by two
injectors (1) in the chamber.
B. Startup system
Once the combustion chamber is ignited, the startup system accelerates the engine until it
reaches its nominal operation speed. This operation is set up by the startup unit (13).
C. Main system
At 97% of nominal operating speed, the main system takes over fuel control and is used to
maintain the desired rotation speed during all the engine operation. These functions are ensured
by the fuel control unit (14).
3. Operation of the fuel system
The fuel from the startup unit and control unit is injected into the engine through an injector
connector (5) followed by a fuel tube (4) and terminated by an injection wheel (3). The injection wheel
sprays the fuel into the combustion chamber (2).
For the three systems, the fuel is pressurized by the same pump (9) built into the fuel control unit.
A filter (8) is located at the inlet of the fuel pump.
At the outlet of this pump, three solenoid valves, for ignition (6), for acceleration (12) and for load (15),
select the different systems to be used. The ignition solenoid valve is also used for draining the ignition
system after operation. A fourth leakage solenoid valve (7) ensures draining of the injection wheel
supply system, when the engine is shut down. Draining of the fuel systems eliminates risks of clogging
and carbonization of the residual fuel. A pressure switch (11) indicates system takeover by the fuel
control unit.
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4. Sequential operation of engine
A. Startup order
When the order for starting up the engine is given, the following are energized: the starter, the
ignition boxes, the acceleration solenoid valve and the startup unit which is applied with pre-set
current. The engine starts rotating, driven by the starter, and fuel flows through the startup unit,
then the fuel metering valve (10) of the control unit, up to the leakage valve which ensures system
purge.
B. Ignition
Two to five seconds after the startup order, the ignition and leakage solenoid valves are
energized, causing the opening of the former and closing of the latter. Fuel is then sent to the
injectors where it is ignited by sparks at the igniter tips. The ignition solenoid valve forces flow of
fuel towards the injection wheel, which carries out spraying, by centrifugal action, into the
combustion chamber, where it is burned by the injectors.
C. Acceleration
Flow of fuel, supplied by the startup unit, progressively increases thus accelerating the engine.
When the rotation speed reaches 55% of nominal speed (993 rpm), the starter, the ignition
solenoid valve and the ignition boxes are de-energized. The ignition system is cut, the air
pressure in the combustion chamber discharges the fuel through the ignition solenoid valve
leakage orifice thus purging the system.
D. Takeover by fuel control unit
At about 97% of nominal engine rotation speed, switchover of the load pressure switch contact
takes place, indicating that the control unit has entered into operation and has taken over fuel
control and engine rotation speed functions.
E. Operation
Two to five seconds after takeover by the control unit, the acceleration solenoid valve is de-
energized and closes whereas the load solenoid valve is energized and opens.
From this moment on, the following operations can be initiated: turbo-generator unit power
supply, nominal speed operation, alternator excitation, etc.
F. Shutdown
When shutdown is requested (normal shutdown, emergency shutdown, system safety shutdown),
all the solenoid valves of the turbo-generator unit are de-energized. De-energization of the
leakage solenoid valve causes its opening thus draining the system by means of the residual
pressure inside the combustion chamber.
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Figure 1 – Fuel system
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FUEL SYSTEM
1. System protection
A. Purpose
When the turboshaft engine is shut down for a period of more than one week or when it is to be
removed, the residual fuel in the control equipment must be free of any traces of water.
B. Means required
(1) Materials:
Test product - HYDROTEST PG-5.
C. Procedure
(1) As soon as the turboshaft engine is shut down, immediately sample a small quantity of fuel
upstream and analyze it to detect presence of water. This analysis is made using
HYDROTEST PG-5:
- the tested product must not change color.
(2) If the product changes color:
- operate the turboshaft engine for five minutes and perform a new test.
NOTE: Repeat this operation until the fuel does not change color of HYDROTEST PG-5.
(3) When the product no longer changes color, the system is protected and does not require any
further operation.
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IGNITION SYSTEM
INJECTORS
1. General
The injectors are used for igniting the combustion chamber. The fuel sprayed by these injectors burns
when in contact with sparks produced by the igniter tips. The fuel sprayed by the injection wheel is
burned in turn by the injectors.
The doubling of the ignition system is an additional safety feature for engine ignition.
The injectors consist of a main body (1) fitted with an attachment flange and a threaded end fitting for
connecting the fuel pipe. In this body, a filter manifold (2) and a nozzle (4) are maintained by a special
nut (3), screwed and welded onto the body.
Figure 1 – Injector
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The filter manifold is formed by a threaded body (3) and a head (7), separated by a groove (6). Two
lateral flats (4) and two other horizontal flats (2) form injector housings in the main body.
The fuel penetrates the two lateral flats through their ends and through a channel (5) drilled into the
manifold. From this point, it goes through the horizontal flats through the threadings of the body which
serve as, for this function, the fuel filter. The filtered fuel fills the groove and is evacuated by a thread
(1) on the head, thus providing fuel turbulence for better distribution by the nozzle.
Figure 2 – Filter manifold
The injectors (3) are introduced into the combustion chamber through drillings made in the bosses of
the turbine casing (5). The injectors are maintained on these bosses by four screws (2). A spacer (1)
fitted with two seals (4) is used for adjusting the depth of the injectors required to reach the combustion
chamber.
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Figure 3 – Injectors assembly
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INJECTORS
A. Check injector attachment and locking of attachment screws.
B. Check condition and attachment of pipes, check tightness of connectors.
2. Removal-installation of a fuel injector
A. Purpose
- Replacement in the event of operation anomaly.
- Replacement of injector after 500 hours of operation.
B. Means required
(1) Systematic spares
202 2 Two lockwashers 73-11 3 3
202 4 Two seals 73-11 3 4
(2) Possible spares (injector-spacer)
202 3 Injector 73-11 3 1
202 5 Spacer 73-11 3 5
(1) Remove the right or left side cover depending on the injector to be removed.
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D. Removal
(1) Removal of pipe (Figure 201)
a) Unscrew connectors (1) and remove pipe (2) connecting the injector to the 3-way
connector.
Figure 201 – Removal-installation of pipe
(2) Removal of injector (Figure 202)
a) Unlock and unscrew the two attachment screws (1) and discard the lockwashers (2).
b) Take out the injector (3) from the turbine casing, discard the two seals (4), recover
spacer (5).
CAUTION: THE SPACER IS ADJUSTED IN FACTORY. DO NOT DAMAGE IT OR

LOSE IT. THE THICKNESS OF THE SPACER IS INDICATED IN THE
ADJUSTMENT SHEET IN THE ENGINE LOG BOOK.
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Figure 202 – Removal-installation of fuel injector
E. Installation
(1) Installation of injector (Figure 202)
a) In the corresponding orifice of the turbine casing, insert the new injector (3) fitted with its
adjusted spacer (5) and the two new seals (4).
b) Position and screw in the two attachment screws (1) fitted with new lockwashers (2).
Tighten and lock the screws.
(2) Installation of pipe (Figure 201)
a) Engage each flexible pipe (2), on the injector taking care of maintaining it in the axis to
avoid twisting it.
Tightening using the two wrenches: maintain in the axial position with a lock wrench and
tighten torque to 7.35 N.m using the torque wrench.
F. Test
(1) Start up the engine and operate it for a few minutes to check for absence of fuel leakage.
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3. Check of an injector
A. Purpose
- To ensure correct flow and regular spray.
B. Periodicity
- Whenever ignition anomaly occurs.
C. Means required
(1) Special tools
The following series of tools are to be procured by the user (see example in Figure 203).
- 1 fuel tank.
- 1 fuel pump with a minimum flow of 6 I/hr at a pressure of 4 bars.
- 1 5-micron filter.
- 1 pressure gauge, graduated from 0 to 10 bars.
- 1 stopwatch.
- 1 test tube.
- 1 template for measuring injector jet angle.
Figure 203 - Installation example for checking an injector
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D. Preliminary operations
(1) Remove the injector (see para. 2 above, page 201).
E. Procedure
(1) Connect the injector on the installation.
(2) Start up the pump. If required, adjust the system pressure to 4 relative bars.
(3) Check spraying:
- the jet must be a perfectly homogeneous mist (no droplets),

- the jet angle must be ≥ 50 degrees (measure using template).
(4) Check flow
- using the test tube and stopwatch, measure the quantity of fuel injected for one minute.
- the flow should be: 84 # Qf # 95 cm3/mm (or yet 5 # Qf # 5.7 l/hr).
(5) If the result is negative, clean the injector (see paragraph 4 below, page 206).
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4. Cleaning of an injector
A. Purpose
- To obtain correct operation (flow and spray).
B. Periodicity
- In the event of anomalies.
C. Means required
(1) Tools
- an oven with a temperature capacity of > 650 °C,

- a stainless steel recipient and a heating element for maintaining a bath at a constant
temperature of 80 °C.
(2) Materials
- Ardrox 185/4.
- Water.
D. Procedure
(1) Cleaning
a) Prepare a mixture of 40 % volume of Ardrox 185/4 and 60 % volume of water.
b) Heat the mixture and maintain this bath at a constant temperature of 80 °C.
c) Soak the injector in this bath for 6 to 8 hours.
d) Remove the injector from the bath and soak it in cold water.
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e) Through the injector, apply a blast of compressed air at 5 bars:
- first, blow the air in the direction opposite to that of normal flow (from nozzle towards
connector),
- then, blow the air in the flow direction (from connector towards nozzle),
- finally, alternately blow in both directions.
f) Check the injector (see para. 3 above, page 204).
- If the result is negative, carry out stoving.
(2) Stoving
a) Place the injector in an oven at a temperature of 650 °C and leave it in place for 2
hours.
b) Remove the injector (asbestos gloves) and allow it to cool down.
c) Check the injector (see para. 3 above, page 204).
- If the result is negative, repeat the stoving operation. If, after this, the result is still
negative, this means that the injector is faulty, it must be returned to the factory.
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STARTUP SYSTEM
STARTUP UNIT
The startup unit comprises two distinct assemblies, but which cannot be functionally separated:
- A valve (3), controlled by a servovalve (4), controls the fuel flow according to the intensity of the
electric signal received. This signal is proportional to the engine rotation speed and to the exhaust
gas temperature. A fuel flow which is too high, results in overheating in the combustion chamber,
and harmful to engine operating life.
- A pressure reducing valve (1) limits the fuel pressure upstream of the valve, as a function of the
downstream pressure such that the flow only depends on the opening angle of the valve.
A plate (2) for adapting and attaching the pressure reducing valve on the valve.
Figure 1 – Startup unit
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2. Servovalve (Figure 2)
The servovalve basically includes an electric torque motor with variable field, biased by a permanent
magnet (5). A blade (1) is secured to a mobile armature (3), mounted on a deflection tube (2). This
armature, located between polarity masses of the magnetic system, is surrounded by two control coils
(4) which, on receiving an electric signal, generate a torque on the armature resulting in displacement
of the blade. The torque obtained and therefore the displacement of the blade depends on the current
intensity crossing the coils. This assembly is housed in a body (6) equipped with a connector (7) for
electrical connection of the coils to the control panel by means of a control harness cable.
Figure 2 – Servovalve
3. Operation of the startup unit (Figure 3)
A. General description
The fuel inlet in the valve is by means of a sleeve (12). It crosses a filter (11) and is driven to the
pressure reducing valve through a channel (10) formed by successive drillings. The pressure
reducing valve includes two chambers (5) and (9), separated by a membrane (6).
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The fuel pressure is checked by the pressure reducing valve by limiting its flow as a function of the
flow authorized in the valve. This limitation takes place by displacement of a needle (7) which,
under the effect of spring (2), more or less blocks a hole drilled in a guide sleeve (8) through which
the fuel flows. A lever (3) moves the needle as a function of the position of the membrane.
A spring (4), in the upper chamber, exerts a certain effort on the membrane which, in the absence
of fuel, completely opens the pressure reducing valve.
The fuel then returns to the valve through channel (1) which spins into two, firstly to supply nozzle
(14) and secondly to supply compensator (16).
The servovalve blade (13) controls opening and flow of the valve by more or less blanking the
nozzle orifice. The compensator needle (17) stabilizes the valve by cancelling the pressure effort
of the fuel applied to the blade by the nozzle.
The fuel flows out from the valve through sleeve (18). Channel (15) formed by successive drilled
holes is used for supplying the upper chamber of the pressure reducing valve.
Figure 3 - Startup unit
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B. Operation
(1) Rest
With the acceleration solenoid valve closed, the startup unit is not supplied with fuel. Spring
(3) exerts a certain force on the membrane (4) which, by means of lever (1), on the needle,
applies a force which is greater and contrary to that exerted by the return spring (12), thus
pushing back the needle and consequently opening the solenoid valve orifice.
At rest, the servovalve (8) causes opening of the valve.
(2) Pre-setting
When the startup order is given, the servovalve is energized which, by means of the blade
(9), tends to close the valve, thus allowing through only the amount of fuel required for igniting
the combustion chamber. At the same time, opening of the acceleration solenoid valve allows
the fuel to pass through the startup unit. On either side of the membrane, the valve upstream
and downstream pressures are established, the downstream pressure through channel (11).
Closure of the valve causes a pressure rise upstream and in the lower chamber (6) of the
pressure reducing valve. This pressure exerts a force on the membrane which resists to the
pressure of the spring (3). Since the load at the needle valve is lesser, the return spring (12)
moves the needle towards the solenoid valve orifice. This results in a drop in fuel flow and
pressure thus creating a balance between upstream and downstream flows.
(3) Acceleration
Acceleration is controlled by the control cabinet by regular attenuation of current intensity

supplying the servovalve up to 0. The blade returns to its initial position and the fuel flow
increases proportionally. A new unbalance of the pressures is established at the level of the
membrane and the valve which, in this case, opens the pressure reducing valve to
re-establish the balance, since pressure in the lower chamber decreases when the valve
opens whereas that of the upper chamber (2) increases.
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Figure 4 - Startup unit operation
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4. Description of startup unit
A. Pressure reducing valve (Figure 5)
The pressure reducing valve consists of a body (1), topped with a cover (5) maintained by four
screws (4). The double membrane is bonded between these two parts. At its center, it has a screw
(13) fitted with two reinforcements (12) and a flange (11). The assembly is secured by a nut (10).
A spring bears on the flange; tension of the spring is adjusted by a screw (8) for varying the
position of its seat (9).
A threaded plug (7), equipped with an O-ring (6), closes access to the adjustment screw.
Assembly of the guide sleeve, the needle and the return spring is performed through a tapped hole
in the body, closed by a threaded plug (2), fitted with an O-ring (3) and on which the return spring
bears. A washer (14) is used for adjusting the overall mechanism.
A lever, between two washers (18), is crossed by a shaft formed by a needle (17). This needle is
housed and held, in a drilling in the body (1), between two balls (16) locked by two screws (15).
Figure 5 – Pressure reducing valve
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B. Valve (Figure 6)
The valve is formed by assembling parts in the main body (3).
The fuel inlet and outlet sleeves, fitted with O-rings (9), are secured to the body by four screws (8).
The fuel is filtered through a grid (7), maintained between a sleeve (6) and a cover (1). The brazed
assembly forms the filter which, fitted with two O-rings (4), is maintained in a drilling of the body by
circlip (5).
The nozzle and compensator, fitted with O-rings (10) and (13), are screwed into the body and
locked by special nuts (11) and (14). The compensator comprises a filtering grid (17) and a screw
for limiting movement of the servovalve range, by means of the compensator needle. O-rings (16)
and (18) ensure tightness of the screw and servovalve, which is riveted to the body.
Certain drilled holes forming circulation channels are blanked by three threaded, headless plugs
(12) and a threaded plug (2).
Figure 6 – Valve
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C. Assembly of startup unit (Figure 7)
Plate (14) is used for coinciding the holes of the three channels drilled into the pressure reducing
valve (17) and the valve (5), through which fuel flows, from one to the other. The plate is secured
to the valve by three screws (2) and is fitted with a pressure reducing valve, secured by four
screws (18). Tightness at the junction is ensured by the central channel, by means of a sleeve
(11), fitted with two O-rings (4), and by a third O-ring (16), for the other two channels by four O-
rings (3) and (15), on either side of the plate.
Figure 7 – Assembly of startup unit
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The fuel inlet and outlet sleeves are respectively fitted with a straight connector (9), followed by an
angle connector (8) and a nipple (7). Tightness is obtained by two O-rings (6), maintained in two
retaining rings (10).
A ring (1) and a plate (13), secured by two rivets (12), enable identification of the unit.
5. Attachment of startup unit (Figure 8)
The startup unit (3) is secured by four screws (4) on the accessory plate (2). Four sleeves (1), located
on the screws, are inserted between the unit and the plate.
Figure 8 – Attachment of startup unit
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STARTUP UNIT
A. Check attachment of unit, locking of lockwire and lead seals.
B. Check attachment and locking of electrical power supply connector of the unit.
C. Check condition and attachment of pipes, check tightness of connectors.
2. Removal-installation of startup unit (Figure 201)
A. Purpose
- Replacement of unit in the event of operating anomaly.
- Removal of acceleration solenoid valve.
B. Means required
(1) Possible spares
202 4 2 O-rings 73-11 2 42
202 1 Startup unit assy 73-11 1 1
(2) Products
- Lockwire.
(1) Remove the right side cover.
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D. Removal
(1) Removal of unit assembly (removal of the acceleration solenoid valve) (Figure 201)
a) Unlock and unscrew knurled nut (12), disconnect the electrical supply connector (11).
b) Unlock tapped connectors (2) on the pressure switches, on which one lockwire is linked
to the startup unit.
c) Unscrew connectors (9) and remove pipe (10).
d) Unscrew and remove four block attachment screws (4), recover their washers (5) and
spacers (3).
e) Unscrew nut from link connector (7) and remove the startup unit (1).
Figure 201 - Removal-installation of startup unit assembly
3. Removal of unit components (replacement of unit) (Figure 202)
A. Unscrew nut from link connector (3) and remove angle connector (6).
B. Unscrew link connector (3) and nipple (5). Recover retaining rings (2) and discard O-rings (4).
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Figure 202 - Removal-installation of startup unit components
C. Installation
(1) Unit components (Figure 202)
a) Fit new O-rings (4), coated with vaseline, onto connectors (3) and (5). Place the
retaining rings (2) on the O-rings, screw in the equipped connectors into their respective
holes on unit (1). Tighten.
b) Install the angle connector (6) on the link connector (3), screw in link connector nut onto
the angle connector, without tightening to enable orientation of the angle connector.
(2) Installation of startup unit assembly (Figure 201)
a) Install the unit (1) on the accessory plate by offering connector (6) in front of link
connector (7) of the acceleration solenoid valve. Screw in nut of connector (7) onto
connector (6), without tightening.
b) Insert spacer (3) between the unit and the accessory plate, aligning with one of the
drillings in the unit through which it will be secured. In this drilling, insert a screw (4),
fitted with its washer (5), and tighten screw into the plate observing that it crosses the
spacer.
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c) Do the same for each screw (4). Tightening can be done once all the screws have been
installed.
d) Tighten the nut of the link connector (7).
e) Install pipe (10) and tighten connectors (9).
f) Tighten nut of link connector (8).
NOTE: This operation is not valid if the startup unit is disassembled for removal of
the acceleration solenoid valve, since components of the startup unit are
not removed.
g) Using lockwire, lock the tapped connectors (2) of the pressure switches.
h) Install electrical power supply connector (11), screw in knurled nut (12) and lock with
lockwire.
D. Test
(1) Start up the engine and operate it for a few minutes to check absence of fuel leakage.
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FUEL CONTROL UNIT
MAIN SYSTEM
1. General
A. Schematic description (Figure 1)
The fuel control unit of the ASTAZOU IV Ml comprises components each of which has a distinct
function; the overall assembly is used for control.
The fuel control unit consists of an oil system for its operation and lubrication. The oil, pressurized
by a pump (15) is channelled by a distributor (14) towards a control system (5), as a function of the
engine rotation speed, measured by a speed detector (13), of the action of an adjustable speed
indicator (9), and of the action of a thermally expandable bulb (10) on which the oil temperature
acts.
Figure 1 – Fuel control unit (schematic diagram)
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The control system which is fitted with an adjustable static control (7) is connected to the fuel
metering valve (4), through which fuel, pressurized by pump (1), flows. The indicator device is
driven by an electric motor (8) and controlled by microswitches (11).
The oil system also consists of a bypass (16) and a check valve (12).
An oil outlet (6) supplies the load pressure switch. The fuel system consists of an pressure relief
valve (2) and a constant ∆p system (3).
B. External description (Figure 2)
The fuel pump and oil check valve are housed in a body (1), followed by a main body (4) which
contains most of the control components. The fuel metering valve and constant ∆p system are
housed in body (2) secured to the left side of the main body. The electric motor (3) and
microswitch unit (5) are maintained on either side at the rear of the main body.
Figure 2 – Fuel control unit
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2. Fuel pump (Figure 3)
The fuel pump is a gear type pump consisting of a drive pinion (11) and a driven pinion (3), mounted on
four bearings (2) and (4) and housed in a body (1), closed by a cover (5) which is secured by two
screws. Tightness of the cover is ensured by an O-ring (10).
The bearings (2), fitted with O-rings (16), are used to, by means of springs (13), catch up lateral play by
sliding in the body.
The bore of the drive pinion includes two series of grooves for driving the pump through a splined shaft
(14) on one hand, and for transmitting movement to the control components through another splined
shaft (7), on the other hand. The two shafts are separated by a clip (12) placed in the pinion. Tightness
of the shaft passage openings is obtained by two lip seals (8), bearing on two rings (6). One set of lip
seals is placed in the cover and the other is maintained in the body by circlip (15).
An O-ring (9) ensures tightness between the pump and main body of the fuel control unit, on which it is
mounted.
Figure 3 – Fuel pump
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3. Pressure relief valve and pressure intake (Figure 4)
A. Description
The pressure relief valve consists of a valve (5) slide-mounted in a guide sleeve (4). A spring (6)
forces the valve to block the sleeve orifice. Spring tension is adjusted by screw (8) which varies
the seating position of the spring (7), which also slides in the guide sleeve. The adjustment screw
is located in a cover (9), maintained with the guide sleeve on the fuel pump body (1) by means of
a screw (11). Three O-rings (12) ensure tightness. Access to the adjustment screw is blanked by a
bonded pellet.
Pressure intake is carried out on the pump discharge channel, through a drilled hole blanked by a
threaded plug (15),fitted with a seal (14).
The fuel inlet and outlet orifices of the fuel pump are fitted with tapped sleeves (2), screwed into
the body.
Figure 4 – Pressure relief valve and pressure intake
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B. Operation
Fuel flows from duct (13) towards duct (16). One part of the fuel is directed towards the pressure
relief valve through duct (3). When there is a fuel overpressure, its pressure exerts a force on the
valve (5). If this force is greater than that of the spring (6), the valve recoils and allows the fuel to
flow towards the suction through notches in the sleeve (4).
4. Oil pump (Figure 5)
The control unit oil pump sucks in oil from the general engine lubrication system and pressurizes the oil
to the pressure value required for operating the fuel control unit. This pump is a gear type pump, which
drives the speed detector.
The drive pinion (7), housed in the main body of the control unit (1), is internally grooved for fitting the
drive shaft (6) coming from the fuel pump (see para. 1). A clip (8) immobilizes this shaft in translation.
The driven pinion (5), by means of a pin (3), is used to drive the flyweight support (4) on which it is
installed.
Two pins (2) ensure centering of the fuel pump unit on the main body, on which it is secured. lt serves
as a cover for the oil pump.
Figure 5 – Oil pump
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5. Speed detector and oil distributor (Figure 6)
The speed detector is used to stabilize the engine rotation speed, required by the indication system, by
acting on the oil distributor supplying the fuel metering valve control system.
Detection takes place by the centrifugal method by two off-centered pivoting flyweights (8), mounted on
a support (3) and indirectly driven in rotation by the engine (accessory drive pinion, fuel pump, oil
pump). These flyweights serve as a lever which, due to offset of the pivoting axis, apply a force which is
proportional to engine rotation, resulting in a centrifugal action. A drawer (18), sliding in the support, is
subjected to the compression force of a spring (10), on one side and, on the other, to the centrifugal
force of the flyweights through a ball stop. This drawer is used for distributing oil to the fuel metering
valve control system, through duct (19). Oil inlet is through duct (17) and discharged through duct (16),
drilled in the drawer.
Depending on the intensity of opposing forces of the flyweights and the spring, the drawer takes
relative positions either for supplying or for discharging the fuel metering valve control system, through
which the engine accelerates (first case) or decelerates (second case).
When the forces are balanced, the drawer is stabilized and prevents oil flow and consequently speed
variation. To obtain a variation, it is simply necessary to destabilize the system by actuating the spring
tension (see next paragraph).
The stop consists of balls (13), held between a cage (14), a sleeve (12) and a washer (11). The sleeve
and washer are maintained in the drawer with an adjustment washer (15) by a special nut (9), on which
the spring (10) bears. The flyweights bear on the cage.
The flyweight support, in rotation in a bearing sleeve (2), undergoes axial thrust by spring (10). This
thrust is countered by a needle stop (4).
The flyweights pivot around a shaft (5) by means of a needle bearing (6). They are centered by four
springs (21), guided by two supports (20). These supports are positioned by flyweight shafts and
maintained surrounded by a bell (7), itself maintained by two pins (22), crimped in the supports.
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Figure 6 - Speed detector and oil distributor
6. Speed control indicator (Figure 7)
In order to vary the engine rotation speed, move the drawer (2) from its stabilized position by varying
the tension of spring (3), which acts on the drawer through the special nut (4) (see preceding
paragraph).
A roller (9), rotating on a shaft (8), held in place by a yoke (7), allows for translation movement of the
shaft according to the rotation of a cam (10), machined on a control shaft, on which this roller rotates.
In the yoke, a thermally-expandable bulb (6) transmits the movement to a sleeve (5), seating of spring
(3).
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Since the rotation speed is a function of the spring tension, it therefore depends on the position of the
control shaft and on the engine oil temperature affecting the bulb.
Guidance of the seating socket and the yoke is carried out by a support socket (12) housed in the main
body (1). It is positioned by a centering pin (16) and maintained with a cover (13), by four screws (14).
Two O-rings (11) and (15) ensure tightness.
Figure 7 - Speed control indicator
7. Fuel metering valve control system (Figure 8)
This system is used to transform a hydraulic pressure, introduced by duct (19), from the oil distributor,
into a rotational movement of the handle shaft (12) which controls fuel metering valve.
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A slide block (11), with two pistons (10) and (15) on either side, receives a translation movement in the
direction of oil pressure applied by piston (10) and in the other direction by a return spring (16), acting
on the piston (15). A spacer (14) connected to the slide block by a shaft (13), transforms this translation
movement into a rotational movement of the handle shaft by sliding it into the latter and pivoting around
its shaft.
The spring is maintained in a cover sleeve (17), secured to the main body (1) by two screws (18).
A stop (9), adjusted by means of a screw (7) through two balls (4), limits return of the spring of the
mechanism to the "Rest" position. It is used for adjusting the engine minimum speed. This assembly is
housed in a sleeve (8), in which a circlip (2) limits movement of the stop. A plate (5), secured by two
screws (6), closes access to the adjustment screw. The sleeve is maintained on the body by two
screws. O-rings (3) ensure tightness.
Figure 8 - Fuel metering valve control system
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8. Fuel metering valve (Figure 9)
The different mechanisms of the fuel control unit, combined together, act finally on the fuel metering
valve since it is the latter which actually carries out all the operations for varying and controlling the
engine rotation speed, by decreasing or increasing the flow of fuel sprayed into the combustion
chamber.
This flow adjustment is carried out by a blanking plug (8) which more or less blanks a hole drilled in a
diaphragm (6), through which the fuel flows. The blanking plug is installed at the end of the handle
shaft (13) and is actuated by a lever (12), maintained on the shaft by a nut pin (9). It is held against a
needle stop (5) by a spring (11). An adjustment washer (4) is used for flush mounting the plug on the
diaphragm. The latter, fitted with a tightness O-ring (2), is centered on the metering valve body (1) by a
pin (3).
The fuel enters the body through an orifice, fitted with a tapped sleeve (10), and exits through another
orifice, also fitted with a tapped socket (7). Both sleeves are screwed into the body.
Figure 9 – Fuel metering valve
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9. Electric motor assembly (Figure 10)
The control shaft (13) is rotated by means of an electric gear motor (3), through a coupling consisting
of two flanges (11) and a drive (12). The gear motor is fitted with a support (9), on which three lugs (10)
are secured and two resistors (5) are attached by four screws (4). These components are used for
wiring the gear motor. The support is secured to the gear motor, along with a protective cover (7), by
six nuts (6) and six washers (8). The cover has three ventilation holes and a notch for electric power
supply cable passage.
A support (1), maintained by four nuts (2) on the gear motor, is used for adapting it to the fuel control
unit.
Figure 10 - Electric motor assembly
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10. Microswitch unit
A. Description (Figure 11)
The speed to be controlled is set in a range delimited by five microswitches (1) which control and
limit the rotation of the control shaft (9). These microswitches are actuated by three cams (8),
through a single lever (11) and two double levers (2). The cams are screwed onto the control
shaft.
The levers and microswitches, with insulating inserts (5) on either side, are secured to three
mobile supports (7) by six screws (6). These supports, separated by two washers (10), are
mounted on a pivoting shaft formed by a needle (18) and maintained by its ends in a support (19).
The contact of the microswitches is adjusted by pivoting the mobile supports around the needle,
by means of three screws (17). Three springs (14) maintain the supports in contact with these
screws, the access of which is blanked by a cover (15) secured to the support by a screw (16).
The assembly is housed in a box (21) by attaching the support to the box by four screws (20). Two
covers (3), maintained by six screws (4), close the box on the top and at the side.
The support is fitted with a connector (13), maintained by four screws (12). The connector is used
for wiring and electric power supply of the microswitch unit and of the electric motor assembly.
Figure 11 – Microswitch unit
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B. Operation: wiring (Figure 12)
The gear motor (3) operates in one direction or the other depending on whether the positive pole
of the electric power supply is connected to one or the other of the terminals. Conversely, the two
terminals are connected to the same negative pole of the power supply through two resistors (2).
This wiring is used to automatically set the terminal to negative, for the terminal which is not
subjected to the power supply.
The two positive power supplies corresponding, one to acceleration and the other to deceleration
of the motor, are connected through two of the five "minimum" (1) and "maximum" (4)
microswitches which, by action of two of the three cams, cut off these power supplies thus
determining the minimum and maximum speeds of the engine, by limiting rotation of the control
shaft.
The third cam actuates a third "utilization" (5) microswitch which, by addition of appropriate wiring,
can be used to set a speed greater than the maximum speed in order to check the overspeed
safety system.
Figure 12 - Wiring
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Wiring consists of connecting the terminal of the "max." open contact to that of the "operation"
common and the terminal of the "utilization" closed contact to that of the "max." closed contact,
which is connected to the gear motor terminal, controlling acceleration. When the microswitch
switches to "max.", the power supply of the gear motor is still effective until the microswitch
switches to "operation", provoked by the third cam. Wiring is performed by means of an electric
sheath inserted between the microswitch unit connector and the control harness power supply
connector.
The cams are adjusted for a "min." engine speed of 97 %, a "max." speed of 108 % and an
"operation" speed of 109 % of nominal speed, at no load, i.e. with the alternator not energized.
11. Adjustable static system (Figure 13)
The static system of the fuel control unit causes an automatic acceleration of the engine which is
inversely proportional to the load exerted by its shaft.
A. Description
A spring (14), secured to the handle shaft (15), applies a traction effort on a screw (7) which,
through a lever (6) and two needles (4), is transformed into a thrust on the special nut (3) of the oil
distribution drawer.
The needles, placed end to end, are maintained in a sleeve (5) between two pellets (2), housed in
the special nut and the lever.
The upper hook of the spring, with washers (17) on either side, is connected to the handle shaft by
a pin (18) maintained by lockwire (16). The power hook, between two threads of the screw, is used
for adjusting the spring tension by varying its position, obtained by turning its screw.
In the screw head, two balls (23), pressed inside the lever bore grooves by a spring (22), are used
for notch-by-notch adjustment. The screw is turned from outside the control unit by a screwdriver
(12) which is inserted through the cover (9) and sleeve (8). Tightness of the cover and sleeve is
ensured by an O-ring (13). A thrust washer (10), maintained on the cover by a screw (11), has a
circular groove for housing the screwdriver collar. This washer consists of a notch which, after
rotating the washer, is used to insert the screwdriver to reach the screw and carry out adjustment.
A circlip (21), at the end of the screw, limits the adjustment.
Two shafts (20), secured on the sleeve (8) by two screws (19), are used for articulating the lever.
The end of these shafts penetrates a groove in the screw (7) for its immobilization in translation.
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Figure 13 - Adjustable static system
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B. Operation
A decrease in the charge of the engine shaft results in closure of the fuel metering valve by
rotation of the handle shaft (see paragraph 6). This rotation causes the spring to be tensioned,
resulting in an additional stress on the drawer in the direction which produces engine acceleration,
proportional to closure of the metering valve, therefore discharging the engine.
This system serves in attenuating the instantaneous decrease of the engine rotation speed, when
the engine is started up.
12. Constant ∆p system
A valve (10), exerted by a spring (8), blanks off the orifice of a sleeve (11), housed and maintained
by a needle (12) in a bore of the metering valve body (1). The valve comprises a clamp against
which are maintained by a nut (13), a membrane support (15), a membrane (9), and a spacer
(14). The membrane, also maintained in a groove of sleeve (11), separates the bore into two
distinct chambers.
The spring bears on the membrane support and on a seat (5) which slides in the bore. The tension
of the spring is adjusted by a screw (2) which varies the position of its seat. This screw is located
in a cover (4) secured to the body by two screws (6). A locked pellet (3) blocks the access to this
screw. Three O-rings (7) ensure tightness.
Figure 14 - Constant ∆p system
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B. Operation (Figure 15)
The constant ∆p assembly maintains a constant ∆p pressure difference between downstream and
upstream of the fuel metering valve such that the flow allowed by the latter only depends on the
position of the plugs (4) with respect to the diaphragm (5).
On either side of the membrane (2), fuel inlet and outlet pressures from the metering valve are
established in such a way that the difference of ∆p pressures recorded in the metering valve is
distributed over the membrane. If the value of this ∆p becomes greater than the limited value set
by the spring (1), the valve (3) moves and allows passage of the inlet fuel which returns to the fuel
pump suction. Thus, irrespective of the inlet fuel pressure, it does not influence the flow.
Figure 15 – Operation of constant ∆p system
13. Control shaft (Figure 16)
The control shaft (17), driven by the electric gear motor, is used to set the engine rotation speed to be
controlled within a certain limit, controlled by microswitches (see para. 6, 7 and 10).
It is installed on two identical bearings each comprising a ball bearing (8), housed in a cage (7).
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The bearings are maintained between the cages and shoulders which are made on the shaft for its
immobilization in translation. The cages are housed in a bore of the main body (1) of the block and
maintained, one with the microswitch unit (3) by two screws (2) and (5), and the other with support (10)
of the gear motor (11) by two screws (12), one of which also maintains a bracket (13) on which it is
secured by a screw (14) and a clamp (15). The electric power supply cable (16) of the gear motor is
maintained by a clamp. The adjustment of axial plays is made by means of two laminated shims (9)
positioned between the ball bearings and the shoulders of the shaft. Two O-rings (4) and (6) ensure the
tightness of each bearing.
Figure 16 - Control shaft
14. Handle shaft (Figure 17)
The handle shaft (13) is used for transmitting movement of the fuel metering valve control system and
also for control unit static system operation (see para. 6 and 10).
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It is installed on two bearings consisting of two ball bearings (7), housed in two cages (4) and (11).
These bearings, installed on the shaft with two other ball bearings (3), are maintained between the
cages and the two half-disks machined on the shaft, through which movement is conveyed. The two
cages are secured to the main body (2), one (4) by two screws (6) and the other (11), with the fuel
metering valve body (14), by two screws (15). A pin (10) ensures centering of the metering valve.
Axial plays and centering are adjusted by a spacer (17) and two laminated shims (5) located between
the bearings. Tightness is ensured by four O-rings (1) and two other O-rings (16), one of which is
retained by a washer (12) placed on the shaft.
The main body includes an additional bore through which certain components of the fuel control unit
are assembled. The bore is blanked by a cover (9) fitted with an O-ring (8) for tightness.
Figure 17 – Handle shaft
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15. Oil by-pass and pressure intake (Figure 18)
A. Description
The oil by-pass comprises a valve (2) pressed against the orifice of a guide sleeve (8) by a spring
(3) bearing on a sliding seat (4). Spring tension is adjusted by movement of the seat, obtained by
a screw (6) located in the cover (5). The sleeve and cover are secured to the main body (1) by a
screw (9). A locked pellet (7) closes access to the adjustment screw. Tightness is ensured by
three O-rings (10).
Pressure intake takes place through a drilled hole fitted with a sleeve (12), on which a nipple (13)
and a plug (14) are screwed. An O-ring (15), held in a ring (16), ensures tightness. The orifices for
oil inlet and supply of the load microswitch are also fitted with tapped sleeves (12). These three
sleeves, fitted with O-rings (11) are secured to the cover by six screws (17).
B. Operation
When the oil is blocked at the level of the distributor (in the event of a stabilization or engine speed
deceleration), its pressure is applied to the valve, recoiling it, allowing this oil to be returned to the
pump suction, through notches in the guide sleeve.
Figure 18 - Oil by-pass and pressure intake
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16. Oil check valve (Figure 19)
A. Description
The check valve consists of a ball (6) guided in a sleeve (3) and pressed by a spring (5) against a
seal (7), maintained in the socket by a valve seat (8) and a circlip (9). The sleeve, fitted with two
O-rings (2), is housed in a bore of the fuel pump body (1) and maintained in place by a circlip (4).
B. Operation
The check valve is used to contain oil until the control unit is completely filled, to allow its
lubrication. It is used to maintain, in the unit, a certain pressure which, as soon as it is exceeded,
pushes the ball to allow oil to flow through notches in the sleeve.
Figure 19 – Oil check valve
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17. Fuel control unit operation at different rates
A. Ignition and startup (Figure 20)
As soon as the engine is driven by the electrical starter, oil pump (1) and fuel pump (4) start to
flow.
After ignition of the combustion chambers by the injectors, startup takes place by the startup unit
(2) which outlets fuel progressively as a function of time and temperature of exhaust gases. With
the load solenoid valve (5) closed, the fuel supplied by the pump is directed to the startup unit,
through the acceleration solenoid valve (3), then returns to the control unit in which it passes
through the fuel metering valve (6).
During startup, the engine rotation speed does not allow the centrifugal force of the flyweights (9)
to be greater than the force of the spring (10) such that the spring totally moves the drawer (8)
opening to maximum to allow passage of oil, from the pump to the control system (7). This results
in complete opening of the fuel metering valve, allowing free passage of fuel which, in this case, is
only controlled by the startup unit.
Figure 20 – Ignition and startup
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B. Takeover (Figure 21)
During engine acceleration, the increase in rotation speed brings about an increase in the
centrifugal force of the flyweights, which tends to reduce the effect of the spring force. At about
97 % of nominal speed, this force becomes greater than that of the spring. The resulting
movement of the drawer discharges oil in the control system. The fuel metering valve closes
consequently until the flow obtained results in a rotation speed which balances the two opposing
forces applied to the drawer. In this state, the drawer blocks oil flow and consequently speed
variation.
At the same time, during closure of the fuel metering valve, rotation of the handle shaft generates
statism which attenuates closing of the metering valve by adding, to the spring force, a force
proportional to the closing of the metering valve such that the nominal speed always be reached
by an acceleration.
Takeover by the control unit is indicated by the pressure drop in the control system, generated by
oil discharge which also supplies the load pressure switch. Its switchover is followed by opening of
the load solenoid valve and closing of the acceleration solenoid valve.
Figure 21 - Takeover
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C. Speed adjustment (Figure 22)
A variation in the tension of spring (1) causes a break in fuel control unit balance and results in
movement of the drawer and consequently speed variation. This variation takes place until a
centrifugal force of the flyweights is created, capable of eliminating unbalance of the drawer which,
once re-established, stops speed variation. This results in a new speed of the engine proportional
to the new tension of the spring (1).
The tension is varied by the gear motor which applies a rotation to the control shaft (6), on which
cam (3) is used to vary the position of seat sleeve (2) by means of yoke (5) and thermally
expandable bulb (4).
Figure 22 - Speed increase
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D. Load increase (Figure 23)
An increase of the load on the engine shaft results in an instantaneous decrease of the rotation
speed and consequently of the centrifugal force of the flyweights. This produces an unbalance of
the drawer which, in its new position, allows oil to pass towards the control system of the fuel
metering valve, to obtain a greater flow and thus re-establish the nominal speed of the engine and,
consequently, balance of the drawer. In fact, the nominal speed is not completely reached
because of the static system produced by opening of the fuel metering unit.
Figure 23 – Load increase
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E. Load decrease (Figure 24)
A decrease in the load of the engine shaft causes engine and control unit reactions which are
similar but inverse to those during load increase: firstly, instantaneous increase of speed causing
an increase in the centrifugal force of the flyweights, unbalance of the drawer and consequently
discharge of oil from the control system, closing of the fuel metering valve until nominal speed is
obtained, slightly higher due to the static system and return to stabilization of the drawer and
speed.
Figure 24 – Load decrease
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18. Assembly and equipment of fuel control unit (Figure 25)
The fuel pump (10) is secured to the front of the main body (8) by four screws (7).
The oil and fuel inlet and outlet orifices are fitted with components for connecting pipes.
The fuel outlet orifice of the pump and fuel inlet and outlet orifices of the fuel metering valve are fitted
with restriction socket (5).
Each orifice of the fuel control unit is fitted with a straight connector (2) for connecting either an angle
connector (1) or a T-connector (6) or both, depending on the orifices:
- angle connector (1) on inlet and outlet orifices of the pump, supply outlet orifice of the load pressure
switch and fuel inlet and outlet orifices of the fuel metering valve,
- a T-connector (6) on the oil inlet orifice,
- a T-connector (6) followed by an angle connector (1) on the constant ∆p system.
Tightness of the straight connectors (2) is ensured by an O-ring (3) maintained in a ring (4). An O-ring
(9) ensures tightness of the circulation inlet orifice.
Figure 25 - Assembly and equipment of fuel control unit
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19. Attachment of fuel control unit (Figure 26)
The fuel control unit (2) is secured on the air inlet casing by two nuts (1).
Figure 26 - Attachment of fuel control unit
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FUEL CONTROL UNIT
A. Check attachment of fuel control unit, check for absence of leakage at different mating faces.
B. Check condition and attachment of pipes, check tightness of connectors.
C. Check attachment and locking of the fuel control unit electric power supply connector.
D. Check locking of attachment screws of various components of the fuel control unit and check for
presence of lead locks at the different adjustment points.
2. Removal-installation of fuel pump pressure relief valve (Figure 201)
A. Purpose
Reconditioning of the pressure relief valve in the event of low or null fuel pressure downstream of
pump.
B. Means required
(1) Spares required
201 4 O-ring 73-21 2 15
201 10 O-rings 73-21 2 19

(Qty. 2)
(2) Products
- Emery paper, grade 000.

- Vaseline.
- Lockwire.
- Solvent.
(2) Remove the bottom cover.
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CAUTION: DURING ALL THE OPERATION, TAKE ALL PRECAUTIONS TO AVOID

DROPPING ANY PART.
D. Removal
(1) Unlock and remove screw (9). Recover washer.
(2) Remove the valve cover (7) without touching adjustment of screw (6).
(3) Remove seat of spring (5), spring (3), valve (2) and sleeve (1).
(4) Discard seals (4) and (10).
E. Check
(1) Check that the bearing surfaces of valve (2) and sleeve (1) are free of scratches.
(2) Make sure that the bore of seat (5) and the rod of valve (2) are free of traces of seizure.
(3) In the event of slight damage, eliminate it using emery paper, grade 000. Clean using
solvent.
(4) Check that the valve slides freely in seat (5) and that it holds perfectly in sleeve (1).
F. Installation of valve
(1) Install new O-rings (4) and (10), coated with vaseline, on the seat of spring (5) and sleeve
(1).
(2) On the seat (5), install spring (3) and valve (2). Insert the assembly in sleeve (1).
(3) Position the equipped cover (7) on the sleeve (1) and insert the assembly into the bore of the
fuel control unit.
(4) Hold the assembly. Screw in screws (9), fitted with a headless washer. Tighten and lock.
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G. Tests
(2) Start up the engine to:
a) Check for absence of leakage.
b) Check the fuel pressure. If necessary, unlock, remove washer (8) and using screw (6),
adjust the pressure to 11,500 HB (engine at 100 %, no load). If necessary, adjust the
speed limits as indicated in paragraph 6 of this section.
c) After adjustment, install washer (8) and lock.
(3) If the anomaly subsists, replace the fuel control unit.
Install the side covers.
Figure 201 - Removal-installation of fuel pump pressure relief valve
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3. Removal-installation of fuel control unit oil pump pressure relief valve (Figure 202)
A. Purpose
Reconditioning of oil pump pressure relief valve if speed is ≤ 40 % and temperature t4 < 350 °C.
B. Means required
(1) Spares required
202 5 O-ring 73-21 4 17
202 11 O-rings (Qty. 2) 73-21 4 21
(2) Products

- Vaseline.
- Lockwire.
- Solvent.
CAUTION: DURING ALL THE OPERATION, TAKE ALL PRECAUTIONS TO AVOID

DROPPING ANY PART.
D. Removal
(1) Unlock and remove screw (10). Recover washer.
(2) Remove equipped cover (6) without touching adjustment of screw (7).
(3) Remove the assembly formed by sleeve (9), seat of spring (4), spring (3) and valve (1).
(4) Discard seals (5) and (11).
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E. Check
(1) Check that:
a) The bearing surfaces of valve (1) and sleeve (9) are free of scratches.
b) The rod of valve (1) and bore of seat (4) are free of traces of seizure.
(2) Remove slight damage using emery paper, grade 000. Clean the parts with solvent.
(3) Ensure that:
a) The rod of valve (1) perfectly slides without hard points in the seat (4).
b) The valve (1) holds correctly on its seating on sleeve (9).
F. Installation
(1) Install new O-rings (5) and (11), coated with vaseline, on sleeve (9) and seat of spring (4).
(2) In the sleeve (9), insert the assembly formed by seat (4), spring (3) and valve (1).
(3) Position the equipped cover (6) on the sleeve (9). Insert the assembly into the bore of the
control unit.
(4) Hold the assembly and secure it with screw (10) fitted with a headless washer. Tighten and
lock.
G. Tests
(2) Remove plug (2) and connect a 0 to 20,000 hPa pressure gauge.
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(3) Start up the engine to:
a) Check for absence of leaks.
b) Check the modulated pressure using the pressure gauge. The pressure should regularly
rise with the engine speed, to reach 9,000 to 10,000 hPa and suddenly drop to between
6,500 and 7,000 hPa when the fuel control unit takes over control.
If necessary, unlock and remove washer (8) and adjust the modulated oil pressure
using screw (7), with the engine running at 100% no-load. If required, adjust the speed
stops as indicated in paragraph 6 of this section.
c) After adjustment:
- Install and lock washer (8).

- Check the modulated pressure once again.
- Stop the engine, remove the pressure gauge and install plug (2). Tighten.
(4) If the anomaly subsists, replace the fuel control unit.
Figure 202 - Removal-installation of fuel control unit oil pump pressure relief valve
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4. Removal-installation of fuel control unit
A. Purpose
Replacement of fuel control unit or of drive shaft in the event of operating anomaly.
Intervention on fuel metering valve in the event of no-load and on-load speed variation.
B. Means required
(1) Spares required
204 5 2 self-locking nuts 73-21 1 2
204 1 O-ring 73-21 2 28
(2) Possible spares
204 2 Drive shaft 73-21 2 2
204 3 Fuel control unit assy 73-21 1 1
(3) Products
- Vaseline.
- Lockwire.
For this operation:

GOGGLES.
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D. Removal
(1) Removal of pipes (Figure 203)
a) Unscrew connectors (17), (15) and (14) and remove pipes (19), (16) and (18).
b) Unscrew the two screws (6) attaching clamps (8); recover their washers (7). Unscrew
connectors (5), and remove pipe (11).
c) Respectively unscrew connectors (1), (13), (10) and (3) and remove pipes (2), (12), (9)
and (4).
NOTE: These pipes may contain a certain quantity of liquid, take the necessary
precautions when removing them.
Figure 203 - Removal-installation of pipes
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(2) Removal of fuel control unit (Figure 204)
a) Unlock and unscrew knurled nut (6), and disconnect electric power supply connector (7)
from the fuel control unit.
b) Unscrew the two self-locking nuts (5), and recover their washers (4).
c) Disengage the fuel control unit (3) from the air inlet casing by pulling it in parallel with
the engine shaft. Separate the fuel control unit from the studs used for its attachment
and remove the unit.
d) Remove the drive shaft (2) from the fuel control unit or from the air inlet casing if it has
remained on one or the other of the parts.
e) Remove O-ring (1) from its housing on the unit and discard it.
Figure 204 - Removal-installation of fuel control unit
E. Check
(1) Carefully examine the condition of the drive shaft. Replace it: if it is the cause of the
operating anomaly. Otherwise, replace the fuel control unit assembly.
(2) Check the tightening torque of the two self-locking nuts, using a torque wrench. Replace
them if the torque read does not correspond to that indicated in chapter 70-10-02.
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F. Installation
(1) Installation of fuel control unit (Figure 204)
a) Install a new O-ring (1) coated with vaseline, into its housing on the unit (3).
b) Insert the drive shaft (2) in the corresponding hole of the unit.
c) Install the fuel control unit by offering the drive shaft in front of the corresponding air
inlet casing orifice; engage the unit in the casing taking care to correctly engage the
shaft in the teeth of the drive pinion, positioning it in such a way that the studs on the
casing engage into the corresponding holes on the fuel control unit.
d) lnstall the self-locking nuts (5), equipped with their washers (4), on the studs. Screw in
and tighten.
e) Install the electrical power supply connector (7). Screw in the knurled nut (6) and lock
using lockwire.
(2) Installation of pipes (Figure 203)
a) Respectively install pipes (4), (9), (12) and (2), screw in connectors (3), (10), (13) and
(1), and tighten.
b) lnstall pipe (11), screw in connectors (5) and tighten. Install clamps (8), screw in the
attachment screws (6), equipped with their washers (7) and tighten.
c) Install pipes (18), (16) and (19), screw in the connectors (14), (15) and (17), and tighten.
G. Test
(2) Start up the engine and operate it for a few minutes to check for absence of leaks.
(2) Top up the tank with oil.
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5. Removal-installation of fuel metering valve (Figure 205)
A. Purpose
Reconditioning of metering valve plug in the event of no-load and on-load speed variations.
B. Means required
(1) Spares required
205 2 O-rings (Qty. 2) 73-21 5 3043
(2) Products

- Solvent.
- Vaseline.
- Lockwire.
Remove the fuel control unit as a safety measure.
D. Removal of fuel metering valve
(1) Unlock and remove the four screws (4).
(2) Remove the metering valve body (9) by slowly extracting it, taking all necessary precautions
to avoid dropping the plug (3) and the spring.
(3) Remove the needle stop (6) and adjustment shims (7) from the bore of diaphragm (5).
(4) Drive out the diaphragm (5) by means of a plastic drift.
(5) Discard O-rings (2).
E. Repair
(1) Place a sheet of grounding paper on a perfectly flat surface and rub the diaphragm (5) on it,
describing a movement in the form of an "8".
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(2) Check the condition of the surface of the plug (3) in contact with the diaphragm (5). Remove
slight scratches using emery paper.
(3) Clean the parts with solvent.
F. Installation of fuel metering valve
(1) On the diaphragm (5), install a new O-ring (7), coated with vaseline.
(2) Position the diaphragm (5) in the body (9), centered by pin (8).
(3) Using vaseline grease, slightly coat the adjustment washers (7), needle stop (6), spring (10)
and plug (3).
(4) In the diaphragm (5), install:
a) The adjustment washer(s) (7) by placing the chamfered side towards the bottom of the
diaphragm.
NOTE: If several washers are installed, first install the thickest washer.
b) The needle stop (6).
(5) On the bearing (1), install an O-ring (2), coated with vaseline.
(6) On the shaft (12), install spring (10) and plug (3), by engaging the lever pin (11) into its
notch.
(7) Position the equipped body (9) on the control unit body.
(8) Install, tighten and lock the four screws.
(9) Re-install the fuel control unit and the pipes.
(10) Install the fuel control unit and the pipes.
G. Tests
Carry out a functional check of the engine.
If the anomaly subsists, replace the fuel control unit.
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Figure 205 - Removal-installation of fuel metering valve
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6. Adjustment of speed limit stops (Figure 206)
A. Purpose
Adjustment of limit stops to reach the maximum and minimum N speeds.
B. Means required
(1) Tools
- 1 screwdriver.
- 1 4-mm angle open-end wrench.
- 1 9-mm open-end wrench.
Remove the right side cover.
D. Adjustment
CAUTION: ON THE ASTAZOU IV M1 ENGINES, THE "UTIL" CAM

CORRESPONDS TO THE OVERSPEED VALUE AT NO-LOAD
(110 %) AND ENABLES CHECKING, DURING STARTUP, THE
OPERATION OF THE OVERSPEED DETECTION SYSTEM. AFTER
SETTING, IT IS FORBIDDEN TO MODIFY THIS ADJUSTMENT.
(1) Fine adjustment
NOTE: Each speed Iimit stop is fitted with a screw for a speed correction of the order of
± 1 % (i.e. ± 18 rpm alternator or 0.6 Hz).
a) Remove screw (2) with its washer and plate (3).
b) Start up the engine and set the speed to the desired limit stop.
c) Screw in or out the corresponding adjustment screw:
- MIN.: minimum speed limit stop,

screw in to decrease.
- MAX.: maximum speed limit stop,
screw in to increase.
d) After each "faster" or "slower" speed adjustment, make sure that the lever (6) of the
microswitch (4) correctly trips at passage of the cam.
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e) After completing the adjustment of the speed limit stop, stop the engine, install the plate
and screw, and tighten.
(2) Adjustment of cams
NOTE:
1. If speed correction is > 1 %, carry out cam adjustment.
2. For this purpose, previously position the fine adjustment screw (1) to the center point.
a) Remove screws (8) and (11), then covers (5) and (9).
b) Start up the engine and set speed to the limit stop to be adjusted (MIN. or MAX.).
c) Immobilize the shaft end of the cams (10) using a 4-mm angle open-end wrench.
d) Using the 9-mm open-end wrench, adjust cam (7) corresponding to the limit stop to be
adjusted:
- by retrieving cam (7) of lever (6) of the microswitch:
Min. N decreases.
Max. N decreases.
- by approaching the cam (7) of lever (6):
Min. N increases.
Max. N decreases.
e) Terminate speed adjustment by screw (1).
f) Ensure correct tripping of microswitch by actuating "faster" and "slower".
g) When the adjustment is over, stop the engine, install the covers (5) and (9), the plate
(3). Secure using screws (2), (8) and (11). Tighten.
h) Since adjustment of the cams is a very delicate operation, if the result obtained after
adjustment is null, replace the fuel control unit.
Install the right side cover.
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Figure 206 - Adjustment of speed limit stops
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FUEL SYSTEM EQUIPMENT
INTERNAL COMPONENTS
To allow its perfect combustion, the fuel is injected in the combustion chamber (4) by a centrifugal
effect. This effect is obtained by rotation of an injection wheel (3) through which the fuel arrives. An
injector connector (1) is used for connection and tightness between the fixed and mobile parts of this
internal fuel system.
A fuel tube (2) connects the injector connector to the injection wheel.
Figure 1 – Internal components
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2. Fuel tube (Figure 2)
The fuel tube consists of a long tube (2) whose channel (1) allows passage of fuel from the injector
connector to the injection wheel.
A welded stop (3) is used for driving it. In addition, it comprises two shoulders (4) used for centering it
with respect to the axial wheel. Its front section comprises six circular grooves in which six sealing
O-rings (6) are installed.
A threading (5) facilitates assembly of the tube with the shaft nose of the rotating assembly.
Figure 2 – Fuel tube
3. Injector connector (Figure 3)
The injector connector consists of parts mounted in a light alloy body (15). lt has a central bore with
decreasing stages and drilled holes used as lubrication channels and for fuel flow
The fuel tube (1) is fitted on a shaft (16) driven in rotation by compression action of the tube O-rings.
This rotation is facilitated by two ball bearings (4) which, separated by a shaft shoulder, are maintained
in a cage (13) by a washer (18) pressed against the bearings by eight springs (19). These springs are
housed in the counter-bores of an oil distributor (20), secured on the body by two screws (2), fitted with
washers (3), which ensure centering of the connector when it is installed on the hub casing of the
reduction gearbox (see chapter 72-10-03).
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The cage (13), positioned by a pin (17) with respect to the distributor, is maintained between the latter
and the body in which it is housed. The oil distributor ensures, through a set of drillings, lubrication of
the injector connector and of parts of the reduction gearbox (see chapter 72-80-04). Oil tightness is
obtained by friction of a Sealol seal (6), housed in the cage (13), with a friction ring (5), maintained on
the shaft by a screw (12) and fitted on this shaft.
A channel (14), drilled in the body, directs the fuel towards the center of the connector in which it is first
introduced in a cage (10), located at the end of cage (13), then penetrates the shaft (16) for being
directed into the fuel tube. A graphite seal (11), bonded into a sleeve (9), ensures tightness between
the rotating parts (screw (12)) and fixed parts (cage (13)), by friction against screw (12). The sleeve,
sliding mounted in the cage, is used to ensure, through a spring (8), permanent contact between the
graphite seal and the screw. This screw comprises a thread for, remaining flush with the cage (10)
during rotation, discharging the oil or fuel, which escapes in spite of the seals, towards a series of
drillings made in the cage (13), to be evacuated through a venting channel drilled in the cage. Several
O-rings (7) ensure the tightness of these parts.
Figure 3 – Injector connector
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4. Injection wheel (Figure 4)
The injection wheel (11) is formed by a disk (9) and a hollow shaft (8), closed by a welded plug (10).
The fuel penetrates the shaft through the fuel tube (2) and is injected, by centrifugal effect, through
radial drillings (13) made in the disk.
The injection wheel is maintained in the rotating assembly of the engine, between the turbine shaft (12)
and the shaft nose (1), in which the wheel shaft engages (see chapter 72-50-02). A sleeve (3), fitted
with two O-rings (16) ensures tightness between the wheel and the shaft nose.
The fuel tube is screwed into the front part of the shaft nose and comes out into the wheel where a
sleeve (7) receives its end. Two sealing washers (5) bearing on two washers (15) are pressed against
a circlip (4), placed in the wheel, by a spring (6), through a guide sleeve (14). Radial expansion thus
obtained by this tightening provides tightness between the fuel tube and the wheel.
Figure 4 –Injection wheel
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5. Driving of fuel tube (Figure 5)
The fuel tube (1) is driven in rotation by the axial compressor (3).
A driver (4) includes two tapes which are inserted in a notch machined at the axial compressor shaft
end. The fuel tube, fitted with an adjustment washer (5), is maintained thrust against the compressor
shaft by screwing the tube into the shaft nose. This screwing is done on the front grooves of the stop
(2). Crimping of the driver bell in the rear groove of the stop enables driving the tube.
Figure 5 – Driving of fuel tube
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INTERNAL COMPONENTS
1. Removal-installation of the fuel injector connector
For the following operation:

TOXIC. IT CAN BE ABSORBED BY THE SKIN AND PENETRATE IN THE
HUMAN BODY. PROTECT HANDS WITH SYNTHETIC RUBBER
A. Purpose
Replacement of connector in the event of a fuel or oil leak or in the event of passage of fuel in oil.
B. Periodicity
A fuel leak is revealed either by a very fast rise in the dilution rate of fuel in oil, or by an increase in
the oil level in the tank if the leak is important.
C. Means required
(1) Special tools
- 2 threaded extractors No. 8810131050
(2) Spares
201 4 6 O-rings 73-31 1 19
201 8 Injector connector 73-31 5 2

assembly
(3) Products
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(1) Remove the alternator motor.
(1) Unscrew the four attachment screws (10) and recover their washers (9) hub casing (5) by
screwing in the extractors alternately, one after the other, quarter-turn by quarter-turn.
(2) Install the extractors (1) in the tapped holes of connector (8), disengage the connector from
the hub casing (5) by screwing in the extractors alternately, quarter-turn by quarter-turn.
(3) Unscrew the extractors from the connector.
(4) Extract the six O-rings (4) from their housing on the fuel tube (6) and discard them.
Figure 201 - Removal-installation of injector connector
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F. Installation (Figure 201)
(1) Install six new O-rings (4), coated with vaseline, in their housing on the fuel tube (6).
(2) Install the connector O-rings (3) and (7), coated with vaseline, in their housing.
(3) Carefully insert the connector on the fuel tube, engage the connector in the hub casing (5),
respecting alignment and positioning: the lubrication outlets (2) must be located towards the
top of the engine, centering is performed by the attachment screw washers of the connector
oil distributor.
(4) Install and screw in four attachment screws (10), fitted with their washers (9) and tighten.
(1) Install the engine on the alternator.
H. Test
(1) Start up the engine and operate it for a few hours.
(2) Check the dilution rate of fuel in oil again and check the oil level in the tank.
2. Cleaning of injection wheel
A. Purpose
During engine operation, combustion residues and fuel carbonization are deposited in the holes of
the injection wheel. Due to this, in the long term, the flow of fuel is reduced until, at the end of a
certain period, the engine can no longer supply the required power and rotation speed. Periodical
cleaning of the injection wheel avoids this phenomenon.
B. Periodicity
- During periodic inspection (see inspection tables in chapter 05-10-02).

- In the event of operating anomaly.
NOTE: A blowing operation through the injection wheel, during each shutdown, can contribute
in spacing cleaning operations.
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C. Means required
(1) Special tools
- Injection wheel cleaning tooling No. 8814932000

including:
- A scraper ∅ 2 ..............................No. 8813057100
- A scraper ∅ 2.5 .........................No. 8813057200
- A scraper ∅ 2.75 .......................No. 8813057300
- A stop for each scraper...............No. 8813057400
- A blowing pipe ..........................No. 8814932500
- A STAUBLI connector ...............No. 8810131125
- A spacer ...................................No. 8814932800
- An inspection lamp ..............................No. 8810533000
- A drive wrench.. ...................................No. 8814958000
- A source of dry compressed air, pressure between 3,000 and 5,000 hPa, with adaptation
connection pipe.
(2) Spares
203 8 Seals 72-41 2 13
(3) Products
- Lockwire.
E. Procedure
(1) Installation of blowing device (Figure 202)
This device is used for blowing dry compressed air inside the fuel system of the engine, to
expel dust particles scraped during the operation, outside the injection wheel.
a) Disconnect electric connectors (1) and (8) supplying the leakage (10) and blowing
solenoid valves (9).
b) Uncouple connector (2) from bracket (3).
c) Disconnect pipe (7) from solenoid valve (10).
d) Remove bracket (3).
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e) Separate the solenoid valves assembly (9) and (10).
f) Install connector (6), pipe (5) and STAUBLI connector (4).
Figure 202 – Installation of blowing system
(2) Installation of drive wrench (Figure 203)
a) Remove the fire detector and the plate located behind the lubrication unit.
b) Position the drive wrench in the hole (2) of the turboshaft engine rear support, until its
end (1) is introduced in the square (3) of the lubrication unit shaft.
Figure 203 – Installation of drive key
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(3) Cleaning (Figure 204)
Cleaning of the injection wheel consists in inserting scrapers into the wheel drillings in order
to detach the particles. This operation is carried out using the three provided scrapers and
which must be used in increasing order of diameter to obtain perfect cleaning.
a) Unlock and unscrew the six screws (5) maintaining the cover (7) of the inspection door
(9) on the turbine casing; recover their washers (6).
b) Remove the cover and discard its seal (8) if damaged.
c) Insert the inspection lamp (4) into the turbine housing through the door then through the
rear drilling of the combustion chamber (10), made for this purpose. Direct the light
beam towards the injection wheel.
d) Turn the rotating assembly by slowly actuating the drive wrench until one hole of the
injection wheel is visible through the front drilling of the combustion chamber.
e) Insert the first 2 mm diameter scraper (3) into the casing then through the front hole of
the combustion chamber, lower it up to the injection wheel. Establish contact with its
point against the wheel next to the hole. Loosen the screw (12) tightening the stop (13)
and lower it on the scraper until it comes into contact with the combustion chamber.
Tighten the screw (12).
f) Remove the scraper from the casing and, using the shim (1) and stop (2), adjust depth
by backing up this stop towards the knurled handle by 36 mm + 0 et – 1.
g) Connect the dry compressed air source (pressure 3 to 5 bars) to the STAUBLI
connector.
h) Insert the scraper again, but this time, penetrating the hole of the injection wheel and by
describing an alternate movement in translation and in rotation, until the stop (13) comes
into contact with the combustion chamber.
i) Perform operations (e, f, g, h and i) with each scraper (successively dia. 2, then dia. 2.5
and dia Ø 2.75).
j) Once the injection wheel is perfectly clean, remove the inspection lamp (4) and
disconnect the compressed air supply.
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k) Close the inspection door (9) with cover (7), fitted with new seal (8) if necessary: screw
in the six attaching screws (5) fitted with their washers (6). Tighten and lock with
lockwire.
Figure 204 – Cleaning of injection wheel
(4) Remove the drive wrench (Figure 203)
a) Remove the drive wrench (1).
b) Install the rear plate and the fire detector on the lubrication unit.
(5) Removal of blowing device (Figure 202)
a) Remove connector (4), pipe (5) and connector (6).
b) Install the solenoid valves in the reverse order to operation 2 E.1) described above.
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G. Test
(1) Perform a ventilation operation.
(2) Start up the turboshaft engine, actuate the "faster" switch and check if the engine reaches
maximum speed.
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SOLENOID VALVES
1. General
The solenoid valves are used for supplying or venting certain equipment items of the engine fuel
system during startup, operation and shutdown phases, as a function of the sequence given by the
electric controls.
2. Description
The solenoid valves are of the direct type (valve built into magnetic core) and are 2-way or 3-way
according to the case.
They comprise a body (3) topped by a control coil (2) fitted with an electrical connection (1).
The 3-way solenoid valve comprises two orifices drilled into the body and one on the coil. The 2-way
solenoid valves only comprise the orifices on the body except the leakage valve which is a 3-way
solenoid valve, one orifice of which is blanked by a plug.
The coil is supplied by a 24 V DC current.
Figure 1 – Solenoid valve
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3. Operation
A. Acceleration and load solenoid valve
Voltage application to the coil causes opening of the solenoid valve. The fuel flows through the
body.
2-WAY
B. lgnition solenoid valve
Voltage cut-off closes the fuel inlet orifice and establishes communication between the two other
orifices for draining the ignition system after operation.
Voltage application to the coil allows passage of fuel through the body, to supply the injectors. The
orifice, on the coil, is closed.
3-WAY
C. Leakage and blowing solenoid valves (Figure 2)
These two solenoid valves are coupled and of the 3-way type.
During sequences "A" (startup -10 seconds after shutdown), the two solenoid valves are switched
off, draining of the main system takes place.
During sequence "B" (engine operation), the blowing solenoid valve (2) is switched off, the leakage
solenoid valve (1) is switched on. Under the action of the coil, the valve closes the leakage system
and allows fuel flow.
Ten seconds after engine shutdown, sequence "C" lasting 60 seconds takes place. The leakage
solenoid valve (1) is switched off whereas the blowing solenoid valve (2) is supplied. The valve
then closes the leakage drain. Dry compressed air, at a pressure of between 4,000 and
5,000 hPa, can flow and drive out combustion residues deposited at the holes of the injection
wheel. After this period, the two solenoid valves are switched off.
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Figure 2 - Operating sequences of leakage and blowing solenoid valves
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4. Assembly and equipment
A. Ignition - acceleration and load solenoid valves (Figure 3)
The ignition (9), acceleration (2) and load (3) solenoid valves are connected by straight connectors
(1) to a 4-way connector (8) through which fuel comes in from the pump.
The two other orifices of the ignition solenoid valve are fitted, one with an angle connector (10)
and the other with a sleeve (11) and an angle connector (10).
A straight connector (1) provides connection of the acceleration solenoid valve to the startup unit.
The load solenoid valve is equipped with a straight connector (1) fitted with a T-connector (4).
Tightness of each straight connector and of the sleeve is ensured by a seal (12) and an O-ring
(13) maintained in a ring (14).
The assembly is secured to the accessory plate (15) of the engine by a lug (5), maintained on the
load solenoid valve by two screws (7) and on the plate by a screw (6).
Figure 3 – Assembly and equipment
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B. Leakage and blowing solenoid valves (Figure 4)
(1) The leakage solenoid valve (9) is fitted:
- At fuel inlet, with a nipple (3) with a set of seals receiving the fuel pipe (4).
- At fuel outlet, with a bracket (2) installed on a union connector (1), with a set of seals.
- At leakage outlet, with a connector (6).
(2) The blowing solenoid valve(s) is fitted:
- At orifice "1", with a union connector (2) with a set of seals.

- At orifice "2" (compressed air inlet), with a nipple (3) with a set of seals, a connector (5) on
which the pipe (7) is installed (7).
- At leakage outlet, with a connector (6) and a connector (5) receiving the leakage drain.
(3) A connector (5) connects both solenoid valves.
Figure 4 - Assembly and equipment of leakage and blowing solenoid valves
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SOLENOID VALVE
A. Check solenoid valve attachment.
B. Check condition of attachment of pipes; check tightness of connectors.
C. Check attachment of coil power supply connectors.
2. Removal-installation of solenoid valve coils
A. Purpose
- Removal of solenoid valves.

B. Means required
(1) Possible spares
201 1 Coil 73-11 4M 20
202 5 Coil 73-11 4M 21
203 13 Coil 73-11 4 9

204 5
203 5 O-ring 73-11 4 5
(2) Products
- Vaseline.
(1) Coil of leakage and blowing solenoid valve
Remove the left side cover.
(2) Coil of ignition, acceleration and load solenoid valve
Remove the right side cover.
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D. Removal
(1) Leakage solenoid valve coil (Figure 201)
a) Disconnect electrical connector (2).
b) Unscrew connector (4) and separate the blowing solenoid valve assembly (3).
c) Remove connector (5).
d) Unscrew nut (6) and remove washer, plate and coil (1) from solenoid valve core.
Figure 201 - Removal-installation of leakage solenoid valve coil
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(2) Blowing solenoid valve coil (Figure 202)
b) Unscrew connector (2) and separate leakage pipe (3).
c) Remove connector (1), screw-washer-plate assembly (4), then coil (5) from the solenoid
valve core.
Figure 202 - Removal-installation of blowing solenoid valve coil
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(3) Ignition solenoid valve coil (Figure 203)
a) Disconnect the coil electrical power supply connector.
b) Disconnect connector (2), remove leakage pipe (1) in the bottom cover.
c) Unscrew nut from angle connector (3), recover retaining ring (6) and discard O-ring (5).
d) Unscrew tapped connector (7).
e) Unscrew attachment nut (8), remove washer (9), plate (10) and coil (13) from solenoid
valve core (12).
Figure 203 - Removal-installation of ignition solenoid valve coil
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(4) Acceleration and load solenoid valve coil (Figure 204)
a) Disconnect the coil electrical power supply connector.
b) Unscrew attachment nut (1), remove washer (2), plate (3) and coil (5) from solenoid
valve core (6).
c) Perform the same operations for removal of acceleration solenoid valve coil (7).
Figure 204 - Removal-installation of load and acceleration solenoid valve coil
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E. Installation of coils
(1) Leakage solenoid valve (Figure 201)
a) lnstall coil (1) on the solenoid valve core, install plate, washer and nut (6) and tighten.
b) Install connector (5) and tighten.
c) Position the blowing solenoid valve assembly (3). Screw in connector (4) on the
connector and tighten.
d) Connect electrical connector (2).
(2) Blowing solenoid valve (Figure 202)
a) Install coil (5) on the solenoid valve core, install plate-washer-nut assembly (4) and
tighten.
b) lnstall connector (1) and tighten.
c) Position the leakage pipe (3), screw in and tighten connector (2).
d) Connect electrical connector (6).
(3) Ignition solenoid valve (Figure 203)
a) Install coil (13) on solenoid valve core (12), install plate (10) and washer (9) on coil,
screw in and tighten attachment nut.
b) Screw in the tapped connector (7) on the leakage orifice of the solenoid valve.
c) Fit a new O-ring (5), coated with vaseline, on angle connector (3), install retaining ring
(6) on the O-ring, screw in the equipped connector in the tapped connector and tighten.
d) Install pipe (1) on the leakage orifice of the solenoid valve. Screw in and tighten
connector.
e) Connect electrical connector (11) on the coil.
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(4) Acceleration and load solenoid valves (Figure 204)
a) lnstall coil (5) on solenoid valve core (6), install plate (3) and washer (2) on coil, screw in
and tighten attachment nut.
b) Connect electrical connector (4) on coil.
c) Perform the same operations for installation of the acceleration solenoid valve coil.
F. Test
Start up the engine and operate it for a few minutes to check operation of coils.
(1) Install left side cover for leakage and blowing solenoid valves.
(2) Install right side cover for ignition, acceleration and load solenoid valves.
3. Removal-installation of solenoid valves
A. Purpose
B. Means required
(1) Spares
209 4 Seal 73-11 4 21

(Qty 2 per solenoid
valve)
209 5 O-ring 73-11 4 19

(Qty 2 per solenoid
valve)
209 4 Seal 73-11 4M 16-17

(1 or 2 according to
solenoid valve)
209 5 O-ring 73-11 4M 14-15

(2 or 3 according to
solenoid valve)
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(2) Possible spares
209 6 Retaining ring 73-11 4 6-20

(1 or 2)
209 6 Retaining ring 73-11 4M 12-13

(2 or 3 according to solenoid
valve)
205 12 Solenoid valve 73-11 4M 19

14
206 7 Solenoid valve 73-11 4 10
207 1 Solenoid valve 73-11 4 11

208
(3) Products
- Vaseline.
(1) Leakage and blowing solenoid valve
Remove left side cover.
(2) Load and ignition solenoid valves
Remove right side cover.
(3) Acceleration solenoid valve
a) Remove right side cover.
b) Remove startup unit.
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D. Removal
(1) Equipped leakage solenoid valve (Figure 205)
b) Unscrew nut (4) and separate fuel pipe (5).
c) Unscrew nut (13) and separate blowing solenoid valve (12).
d) Unscrew nut (3), remove bracket (2) and equipped solenoid valve (14).
(2) Equipped blowing solenoid valve (Figure 205)
b) Unscrew nuts (7) and (10) and separate pipes (8) and (9).
c) Unscrew nut (13), remove solenoid valve (12).
d) Unscrew the three connectors (6).
Figure 205 – Removal-installation of leakage and blowing solenoid valves
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(3) Equipped ignition solenoid valve (Figure 206)
b) Unscrew connector (3) and remove pipe (4).
c) Remove angle connector (2) and retaining ring. Discard O-ring.
d) Unscrew connectors (8) and remove pipe (1).
e) Unscrew nut of straight union connector (6) and remove solenoid valve (7).
Figure 206 - Removal-installation of ignition solenoid valve
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(4) Equipped acceleration solenoid valve (Figure 207)
b) Unscrew nut (3) from straight union connector.
c) Remove acceleration solenoid valve (1).
Figure 207 - Removal-installation of acceleration solenoid valve
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(5) Equipped load solenoid valve (Figure 208)
b) Unscrew connectors (7) and remove pipe (8) if necessary.
c) Unscrew connectors (2) and (6) and remove pipes (1) and (9).
d) Unscrew nut from straight union connector (4) and remove T-connector (5).
e) Unscrew both attachment screws (10) and recover washers (11).
NOTE: If this operation cannot be performed (screw access problems), proceed as

follows:
- Unscrew screw (15), recover washer (16).
- Once the solenoid valve is removed, unscrew both attachment screws
(10), recover washers (11) and remove support (14).
f) Unscrew nut from straight union connector (12), and remove solenoid valve (3).
Figure 208 - Removal-installation of load solenoid valve
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(6) Disassembly of solenoid valves (Figure 209)
According to the type of solenoid valve removed:
a) Unscrew connectors (1), (3), (7), (8) and (10).
b) Recover retaining rings (6).
c) Discard seals (4) and (5).
NOTE: Seal (4) does not exist for angle connectors.
d) If necessary remove nut (2), washer plate and coil (9).
Figure 209 - Disassembly-assembly of solenoid valves
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E. Installation of solenoid valves
CAUTION: FOR ASSEMBLY OF CONNECTORS AND INSTALLATION OF

SOLENOID VALVES, OBSERVE THE DIRECTION INDICATED BY
ITEMS 1 AND 2 ENGRAVED ON THE SOLENOID VALVE BODY.
(1) Assembly of solenoid valves (Figure 209)
a) If the solenoid valve is bare, assemble coil (9), plate, washer and nut (2). Position the
coil (9) and tighten nut (2).
b) Fit equipment on the following:
- Connectors (3) and (7) with an O-ring (5) coated with vaseline, a ring (6) and a seal
(4).
- Connector (10) with an O-ring (5) coated with vaseline, and a ring (6).
c) Onto the corresponding orifices of the solenoid valve, screw in connectors (1), (3), (7),
(8) and (10). Do not tighten.
(2) Leakage solenoid valve (Figure 205)
a) Screw in connector (2). Do not tighten.
b) Position solenoid valve (14). Screw in nut (3). Assemble pipe (5) and tighten nut (4).
c) Install blowing solenoid valve (12). Screw in nut (13) of connector (6).
d) Tighten all connectors and nuts.
e) Connect electrical connector (1).
(3) Blowing solenoid valve (Figure 205)
a) Screw in the three connectors (6). Do not tighten.
b) Position solenoid valve (12). Screw in nut (13).
c) Place pipes (8) and (9). Screw in nuts (7) and (10).
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d) Tighten all connectors and nuts.
e) Connect electrical connector (11).
(4) Ignition solenoid valve (Figure 206)
a) Position solenoid valve (7) on 4-way connector (5). Screw in nut (6).
b) lnstall an O-ring coated with vaseline and a retaining ring (Fig. 209, items 5 and 6) on
the angle connector (2).
c) Screw in connector (2) without tightening. Position pipe (4) and screw in nut (3).
d) Position pipe (1) and screw in two nuts (8).
e) Tighten all connectors and nuts.
f) Connect electrical connector (9).
(5) Acceleration solenoid valve (Figure 207)
a) Position solenoid valve (1) on 4-way connector (4).
b) Screw in and tighten nut (3).
c) Connect electrical connector (2).
(6) Load solenoid valve (Figure 208)
a) Position solenoid valve (3) on 4-way connector (13) and on support (14).
b) Screw in nut (12) without tightening.
c) Screw the two attachment nuts (fitted with their washers) and tighten.
NOTE: If support (14) was removed, proceed as follows:
- Install support on solenoid valve, screw in the two attachment screws

(10) fitted with their washers (11) (by hand and without tightening),
taking care to correctly position the support with respect to the
accessory plate, in order to screw in screws (15).
- Screw in screws (15) fitted with a washer (16) and nut (12).
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d) Install T-connector (5) on straight union connector (4).
e) Screw in nut of straight connector (4) on T-connector (5) without tightening such that it
can pivot for its orientation.
f) Install pipes (1) and (9), screw in connectors (2) and (6).
g) Tighten all connectors, nuts and screws.
F. Test
(1) If necessary, install the startup unit (after installing the acceleration solenoid valve).
(2) Start up the engine and operate it for a few minutes to check operation of the solenoid valve.
(3) Check for absence of leaks.
(1) Install the left side cover after assembling the leakage and blowing solenoid valves.
(2) Install the right side cover after assembling the load, acceleration and ignition solenoid
valves.
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ACCESSORIES
1. General
In addition to equipment installed on the startup unit, the fuel control unit and the solenoid valves, the
engine includes other accessories which are used for connecting pipes.
Since there are two fuel injectors, a 3-way connector (7) allows fuel distribution to these injectors. It
comprises an inlet orifice and two outlet orifices, each equipped with a nipple (3) itself fitted with a
tightness seal (4). The connector is secured with a clamp (6) by means of two screws (5) on a lug (8)
which is itself maintained by two screws (1) securing it to the turbine casing (2), on the air inlet casing.
The clamp holds one of the ignition cables.
Figure 1 - Accessories
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PIPES
1. General
A pipe network connects the different system components to form the fuel system itself.
2. Internal pipes (Figure 1)
A tube (1) with two tightness O-rings (2) is used for driving fuel from outside the engine towards the
hub casing (7) of the reduction gearbox, in which drilled channels guide it towards the injector
connector (see chapter 72-10-03). This tube is held between the hub casing and the oil tank casing (6)
by a connector (4), secured by three screws (5) on the oil tank casing. An O-ring (3) ensures tightness
of the connector.
Venting of the injector connector takes place similarly, but on the opposite side of the engine.
Figure 1 - Internal pipes
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3. External pipes (Figure 2)
General fuel inlet takes place by an assembly of parts secured to the front frame of the enclosure. A
connector (12) crosses the frame and is held in place by a nut (11). On its front threading, an angle
connector (13) is screwed in, on which, an end fitting (14) fitted with a clamp (15) is used for connecting
the pipe from the fuel tank.
On its rear threading, the following are respectively screwed in, one over the other: a straight connector
(10), a filter (9) with sealing washers (8) on other side, and a nipple (7) connected with a pipe (2) which
drives the fuel towards the outlet orifice of the constant ∆p system of the fuel control unit. At this point,
a pipe (6) channels the supply fuel and that discharged by the constant ∆p system towards the inlet of
the fuel pump. This pump discharges the fuel into a pipe (20) which drives it to the 4-way connector.
Through solenoid valves, this connector distributes the fuel to the various systems. Pipe (2) is made of
a flexible hose equipped at both ends with crimped union connectors.
The fuel used for startup is driven through a pipe (4), from the startup unit, towards the T-connector
which fits the load solenoid valve. Then, from this connector, the fuel is supplied to the fuel metering
valve inlet through pipe (5), through which also flows the load fuel.
A pipe (17) connects the fuel metering valve outlet to the engine inlet orifice. The pipe is held on the air
inlet casing by a clamp (18), secured by a screw (19).
The ignition fuel is driven through a pipe (1), of the ignition solenoid valve, towards the 3-way
connector. From this connector, two pipes (21) lead out to distribute this fuel to the injectors.
Venting orifices on the injector connector and on the leakage solenoid valve are respectively fitted with
flexible pipes (16) and (22).
The venting orifice of the ignition solenoid valve is fitted with a rigid pipe (3) on which a flexible pipe is
connected for draining purposes.
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Figure 2 – External pipes
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PIPES
A. Check condition and attachment of pipes; check tightness of connectors.
B. Check locking of fuel filter.
2. Removal-installation of filtering element of fuel filter (Figure 201)
A. Purpose
- Check or replacement of filtering element.
B. Periodicity
- During periodic inspection for 500 hours of operation.

- In the event of operating anomaly.
C. Means required
(1) Spares
201 4 O-ring 73-11 5 12
(2) Possible spares
201 5 Filtering element 73-11 5 13
(3) Products

- Lockwire.
(1) Remove right side cover.
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E. Removal
(1) Unscrew connector (2) and remove pipe (1).
(2) Unlock and unscrew plug (3), take out the O-ring (4) from the plug and discard O-ring.
(3) Take out the filtering element (5) from body (6).
Figure 201 - Removal-installation of filtering element of fuel filter
F. Check
(1) Carefully check condition of filtering element. Replace it if necessary.
(2) Systematically replace the filtering element as per the periodic inspection tables (see
chapter 05-10-02).
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G. Installation
(1) Install a new O-ring (4), coated with vaseline, in plug (3).
(2) Insert the filtering element (5) into body (6).
(3) Screw in the plug on the body and tighten. Lock using lockwire.
(4) Install pipe (1), screw in and tighten connector.
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IGNITION
TABLE OF CONTENTS
Electric generation
- High power generator 74-10-01 1 and 2

Distribution
- Igniters 74-20-01 1 and 2

- Igniter cables 74-20-02 1 and 2
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IGNITION
74 1 May 1981
2 Sept. 1995
74-10-01 1 Dec. 1983

2 May 1981
201 May 1981

202 May 1981
203 May 1981
74-20-01 1 Dec. 1983

2 May 1981
201 Sept. 1995

202 May 1981
203 May 1981
74-20-02 1 Dec. 1983
201 May 1981

202 Sept. 1991
203 Sept. 1991

1995
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ELECTRIC GENERATION
HIGH ENERGY GENERATOR
1. General
The high energy generators, by means of igniters, are used for generating sparks for igniting the fuel
sprayed by the injectors in the combustion chamber.
These high voltage generators are entirely transistorized.
They consist of an assembly of electrical components enclosed in a metallic unit (4). The unit is closed
by a cover (5), secured by four screws (6). Each of them is connected with two electrical power sockets
(2) and (7) for connecting the power supply cable from the control harness and ignition cables which
connect them to the igniters. An identification plate (3) is riveted on the cover.
Figure 1 - Generators
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3. Operation
The high energy generators convert, by discharging of a capacitor, the 24 V DC input current into a
series of electrical pulses having a voltage of 20,000 V. This produces sparks at the igniters, having a
power of 2 joules and a frequency of 400 sparks per minute.
These generators can operate at temperatures of between – 30 °C and 100 °C, and consume 1 to
1.5 A.
The high energy generators (8) are installed side by side and secured by four screws (1), on the engine
accessory plate (9).
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HIGH ENERGY GENERATORS
1. Removal-installation of generator units
A. Purpose
B. Means required
(1) Spares
201 7 Generator 74-21 1 8
(2) Products
- Lockwire.
WARNING: THE ELECTRIC DISCHARGE FROM A HIGH ENERGY IGNITION

UNIT CAN KILL. THE LOW VOLTAGE POWER SUPPLY OF THE
HIGH ENERGY UNIT MUST BE CUT OFF. THEN WAIT FOR AT
LEAST ONE MINUTE BEFORE TOUCHING THE HIGH ENERGY
UNIT FOR DISCONNECTING THE IGNITION CABLES OR
IGNITERS. IT IS FORBIDDEN TO OPERATE THE HIGH ENERGY
IGNITION UNIT IN AN ATMOSPHERE CONTAINING FLAMMABLE
VAPORS.
(1) Unlock and unscrew the knurled nut (9) and disconnect the electric power supply connector
(8) from the unit.
(2) Unlock and unscrew connector (1) and disconnect the igniter cable (2).
(3) Loosen the two attaching screws (5) by a few turns.
(4) Raise the unit (7) until the heads of the attaching screws pass through the two holes (6) in
the accessory plate (3). Pull the unit perpendicularly to the plate.
(5) Once the unit comes off the plate, completely unscrew the attaching screws and recover
their washers (4).
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Figure 201 - Removal-installation of igniter unit
E. Installation (Figure 201)
(1) On the new unit (7), screw in the attaching screws (5), by a few turns, fitted with their
washers (4).
(2) Install the unit on the accessory plate (3) by inserting the attaching screws into the large
holes (6) of the plate, lower the unit so that the screws enter the hole machined below the
large holes, taking care that the washer slides behind the accessory plate.
(3) Screw in and tighten the attaching screws.
(4) Install the igniter cable (2), screw in and tighten connector (1). Lock with lockwire.
(5) Connect the electric connector (8), screw in knurled nut (9) and lock with lockwire.
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F. Test
(1) Start up the engine and operate it for a few minutes to check operation of the units.
(1) Install the right side cover.
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DISTRIBUTION
IGNITERS
1. General
The two igniters convert the current generated by the two generators into sparks. These sparks burst
near the injectors thus igniting the fuel sprayed by the injectors.
This is a high energy igniter with coaxial electrodes.
It consists of a tube (4) at the end of which a spark bursts, a flange (3) for its attachment, and a
threaded end fitting (2) on which the power supply cable connecting it to the generator is screwed.
3. Operation
The igniter is supplied with electrical pulses from one of the two generators. The very high voltage of
these pulses produces high energy sparks.
Figure 1 - Igniter
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The igniter (5) is introduced into the combustion chamber through a drilling of one of the bosses (8) on
the turbine casing. It is maintained on this boss by two screws (1). A spacer (6) with seals on either
side (7) is used for adjusting the insertion depth of the igniter in the combustion chamber so that the
spark is produced across the fuel jet sprayed by the injectors.
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IGNITERS
A. Check attachment of igniters and locking of attaching screws.
2. Removal-installation of igniters
A. Purpose
- Check wear of electrodes.

- Replacement of igniters in the event of excessive wear or operation anomaly
(see chapter 74-20-01, page 203).
B. Periodicity
- During periodic inspection, every 1,000 hours of operation.
C. Means required
(1) Special tools
- Depth gauge
(2) Spares
201 3 2 lockwashers 74-21 1 5
201 5 2 seals 74-21 1 6
(3) Possible spares
201 6 Igniters 74-21 1 3
201 4 Spacer 74-21 1 7
(4) Products
- Lockwire.
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(1) Remove the right or left side cover depending on the igniter to be removed.

VAPORS.
(1) Unlock and unscrew connector (7), disconnect igniter cable (1) from igniter (6).
(2) Unlock and unscrew the two attaching screws (2). Discard lockwashers (3).
(3) Remove the igniter from the turbine casing. Recover spacer (4) and discard seals (5).
CAUTION: THE SPACER IS ADJUSTED IN FACTORY. IT IS RECOMMENDED NOT

TO DAMAGE IT AND AVOID LOSING IT. THE SPACER THICKNESS IS
GIVEN IN THE ADJUSTMENT SHEET IN THE ENGINE LOG BOOK.
Figure 201 – Removal-installation of an igniter
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F. Check (Figure 202)
(1) Using a depth gauge, measure the depth of the central electrode (2) with respect to the earth
electrode (3).
- If the depth is greater than 4 mm, discard the igniter.

- If the depth is less than 4 mm, preserve the igniter.
Figure 202 – Igniter wear check
G. Installation (Figure 201)
(1) In the corresponding hole of the turbine casing, insert the igniter (6) fitted with its spacer (4),
with new seals (5) on either side.
(2) Install and screw in the two attaching screws (2) fitted with new lockwashers (3). Tighten and
lock.
(3) Install the igniter cable (1) on the igniter, screw in connector (7). Tighten and lock with
lockwire.
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DISTRIBUTION
IGNITER CABLES
1. General
The igniter cables ensure conduction of electric current from the high energy generators to the igniters.
The very high voltage current requires a special structure for protecting the cables.
These are shielded coaxial cables.
They are connected through a connector (3) which screws onto the igniter and the generator sockets. A
tube (4), terminated by a spring (5), is used for better electrical contact by pressure. The end, secured
to the igniter, consists of a right angle (2). Protection is ensured by twisted shielding (1).
Figure 1 – Cables-igniters
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IGNITER CABLES
A. Check attachment of cables and locking of attaching connectors.
B. Check attachment of long cable clamp.
2. Removal-installation of igniter cables
A. Purpose
B. Means required
(1) Possible spares
201 7 Short cable 74-21 1 1
201 4 Long cable 74-21 1 2
(2) Products
- Lockwire.
(1) Removal of right igniter cable (short cable)
a) Remove the right side cover.
(2) Removal of left igniter cable (long table)
a) Remove both side covers.
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D. Removal

VAPORS.
(1) Removal of short cable
a) Unlock and unscrew connectors (6). Remove the short cable (7).
(2) Removal of long cable
a) Unscrew the attaching screw (2) from clamp (3) and recover its washer.
b) Open the clamp by separating its two attachment lugs, remove the clamp from its sleeve
and remove this sleeve from the cable.
c) Unlock and unscrew connectors (5). Remove the long cable (4).
Figure 201 - Removal-installation of igniter cables
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E. Installation
(1) Installation of short cable
a) Install the short cable (7), screw in connectors (6), tighten and lock with lockwire.
(2) Installation of long cable
a) Install the long cable (4), screw in connectors (5), tighten and lock with lockwire.
b) lnstall the clamp sleeve on the cable, on the part located at the level of the 3-way
connector (1). Slide the clamp (3) onto its sleeve, pinch its attachment lugs for
assembly.
c) lnstall the clamp installed on the 3-way connector, screw in the attachment screw (2)
fitted with its washer. Tighten.
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ENGINE INDICATING
TABLE OF CONTENTS
Rotation speed indication
- Magnetic sensor 77-10-01 1 and 2

Temperature t4 indication
- Pyrometric harness 77-20-01 1 to 5

- Thermal probe 77-20-02 1 and 2

1991
1
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ENGINE INDICATING
77 1 Sept. 1991
2 Sept. 1995
77-10-01 1 Dec. 1983

2 Sept. 1991
201 Sept. 1995

202 Sept. 1991
203 Sept. 1991
77-20-01 1 May 1981

2 May 1981
3 May 1981
4 Dec. 1983
5 May 1981
201 Sept. 1991

202 Sept. 1991
203 Sept. 1991
204 Sept. 1991
205 Sept. 1991
206 Sept. 1991
207 Sept. 1991
208 Sept. 1991
209 Sept. 1991
210 Sept. 1991
211 Sept. 1991
77-20-02 1 Dec. 1983

2 Dec. 1983
201 May 1981

202 Sept. 1995

1995
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ROTATION SPEED INDICATION
MAGNETIC SENSOR
1. General
Associated to an indicator on the control panel, the magnetic sensor measures and indicates engine
rotation speed.
This is a permanent magnet type sensor for phonic wheel. It consists of a bulb (4) terminated by a
sensor pin (5) and a body (2), fitted with a union connector (1). Between the two, a flange (3) is used
for attachment.
Figure 1 – Magnetic sensor
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3. Operation
The magnetic sensor is located radially in front of the toothed wheel of the reduction gearbox, the teeth
of which are flush with the pin. Each passage of a wheel tooth in front of the pin produces a magnetic
pulse which generates an AC electric current with a frequency proportional to the rotation speed of the
turboshaft engine. This current is transmitted to the electric control panel, through a control harness
cable.
The magnetic sensor (2), fitted with its tightness O-ring (3), is maintained by two screws (1) on the
drilled boss (4) of the oil tank casing. The sensor plunges into the casing and its pin is flush with the
wheel teeth of the intermediate pinion assembly.
Figure 2 – Assembly of the magnetic sensor
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MAGNETIC SENSOR
A. Check attachment of sensor, tightness and locking of attachment screws.
B. Check attachment and locking of the sensor electric power supply connector.
2. Removal-installation of magnetic sensor
A. Purpose
- Replacement of sensor in the event of operation anomaly.
B. Means required
(1) Spares
201 3 Magnetic sensor 77-21 2 23
201 4 O-ring 77-21 2 26
201 5 2 lockwashers 77-21 2 25
201 / Lockwire / / /
(2) Products
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(1) Unlock and unscrew the knurled nut (2), disconnect the electric power supply connector (1)
from the sensor.
(2) Unlock and unscrew the two attaching nuts (6). Discard the lockwashers (5)
(3) Take out the sensor (3) from the oil tank casing.
(4) Remove O-ring (4) from the sensor and discard O-ring.
Figure 201 - Removal-installation of magnetic sensor
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(1) Fit a new O-ring (4), coated with vaseline, on the bulb of the new magnetic sensor.
(2) Insert the sensor into the orifice on the corresponding boss of the oil tank casing.
(3) Install and tighten the two attaching screws (6), fitted with new lockwashers (5). Tighten and
lock.
(4) Connect the electric power supply connector (1), screw in the knurled nut (2) and lock with
lockwire.
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TEMPERATURE T4 INDICATION
PYROMETRIC HARNESS
Associated to an indicator located on the control panel, the pyrometric harness is used for continuous
measurement of temperature t4 of the turbine outlet exhaust gases. This measurement enables
checking operation of the engine and information concerning correct startup operations (temperature
rise). The harness comprises four thermocouples (1) connected in parallel to a connection unit (2) to
which a control harness cable, connecting the control panel, is connected.
Figure 1 – Pyrometric harness
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2. Thermocouple (Figure 2)
A. Description
Each thermocouple consists of a cable (15), protected by a metallic sheath (9) and fitted at each
end with brazed connectors (7) and (13). The cable comprises two conductors, one made of
Chromel and the other made of Alumel. These are connected, as a loop (2), by welding, to the end
of a probe.
This probe consists of a tube (19) and two half-tubes (18), housed in a body (4) between two end
beads (3), one of which is maintained by a bead support (17). It is attached to the sheath by
connector (7) which screws onto the body and is locked by a key (6). It comprises an attaching
nut (5) and two centering pins (1). The empty spaces of this probe are filled by insulating cement.
The cable is maintained in the connector (13) by an end fitting (14), crimped onto the cable. Two
series of 50 beads (16) insulate a section of the conductors in the sheath. These conductors,
identified by sleeves (10) marked AI and Cr, are fitted with connection lugs (11) and protected by
sleeves (12).
The thermocouple is identified by a ring (8) located on the connector (7).
Figure 2 - Thermocouple
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B. Operation
The end loop of the probe is exposed to the exhaust gas temperature. The different types of
metals used in the conductors determine, at the weld point, a potential difference which is
proportional to its temperature and therefore to that of the exhaust gases.
The four thermocouples are connected in parallel through the connection unit thus providing
accurate measurement of the highest temperature of the four welded points.
3. Connection unit
The four thermocouples are connected to a unit (3), closed by a cover (2) and maintained by a
lock on the central support (12) of the unit. Inside, secured by four screws, two junction boxes (5)
receive their conductors, retained by nuts. Four other conductors (13) provide for box wiring.
An adjustable resistance (14) is added to the system. It is maintained on a plate (16) by two
screws and nuts; the plate is secured to a support column (15) by a screw.
Figure 3 – Connection unit
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The cable from the control harness crosses a tube (8), maintained on the unit by biting action of a
conical ring (9), obtained by tightening, between a receptacle (10) and a conical cup (7), by a
ring (6), which screws onto the receptacle, and secured to the unit by four screws.
Two nuts (11) are riveted on the unit for its attachment and an identification plate (1) is bonded to
the cover.
B. Wiring (Figure 4)
Each junction box (7) comprises two terminals (2), one of which is fitted with Alumel conductors
and the other with Chromel conductors. It also comprises two thermocouples (6). The box
terminals, which are fitted with conductors of the same type, are connected together thus enabling
connection of the four thermocouples in parallel.
The potential difference, created by the temperature between the Chromel and Alumel conductors,
is transmitted to an electronic system (4) by means of a cable (5) from the control harness. This
potential difference is made uniform by the adjustable resistor (1) located in parallel with the
thermocouples.
Figure 4 – Wiring
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4. Assembly of harness (Figure 5)
The connection unit (2) is secured by three screws (4) on one lug (3), maintained by two screws (5) for
attachment of the exhaust diffuser (6) on the turbine casing. This diffuser comprises four threaded and
drilled bosses (8) through which passage and attachment of the thermocouple probes (7) take place.
Their sheaths are maintained against each other by clamps (1).
Figure 5 – Assembly of pyrometric harness
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PYROMETRIC HARNESS
A. Check attachment of unit.
B. Check attachment of thermocouples and locking of attachment connectors.
2. Check of a thermocouple
A. Purpose
- Correcting temperature t4 indication anomalies.

- Systematic checks according to periodicity.
B. Means required
(1) Control equipment
- Multimeter (e.g.. METRIX multimeter).

- Insulation tester at 45 V DC (e.g.: PEKLY ISOP 401).
(2) Products
- Mineral graphite vaseline as per standard 4247.

- Lockwire.
(2) Unlock and unscrew each of the four nuts attaching the thermocouple probes on the exhaust
diffuser.
(3) Separate the probes from the diffuser.
D. Visual inspection (every 250 hours)
(1) The loop (1) must be neither crushed nor broken.

In particular, examine the welding (2).
(2) The ceramic (3) must not be broken.
(3) The loop and ceramic assembly must not be pushed completely inside the metallic tube (4).
(4) Check that the wear (5) of the thermocouple wires at the passage of the ceramic does not
exceed 1/3 of the wire diameter.
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Figure 201 – Inspection of probe
(5) If necessary, replace the thermocouple which shows one of the above faults, according to
the indications in paragraph 3.
(6) Install the thermocouple probe as instructed in paragraph 3. D below.
E. Electric checks (every 500 hours)
(1) Voltage check (Figure 202)
Remove the unit cover by unscrewing the knurled screw.
Check voltage of the thermocouples as follows:
- Connect the multimeter leads (scale set to µV) to the Chromel and Alumel terminals.
- Read the voltage indicated and refer to the table in Figure 202 to get the corresponding
temperature.
- Compare this value with that on the temperature t4 indicator of the control desk.
- A deviation of more than 25 °C should initiate a complete check of the temperature t4.
NOTE: This check can be performed by taking two reference points

(example: turboshaft engine cold and at idle).
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NICKEL CHROME NICKEL ALLOY THERMOCOUPLE
Figure 202 – Equivalence table (µV ¥ °C)
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(2) Continuity and insulation check
a) Check the continuity between the Chromel and Alumel conductors.
b) Check insulation as follows:
- Connect one of the insulation tester leads to the metallic sheath of the thermocouple,
and the other to the Chromel and Alumel lugs combined.
- The insulation at 45 VDC must be greater than 0.5 MΩ.
c) Perform the same checks for each of the four thermocouples and replace the faulty
thermocouple(s).
d) Re-connect each thermocouple to the corresponding lugs inside the unit.
- The Chromel and Alumel lugs are identified by difference in diameter.

- Tighten the nuts to the torque indicated in chapter 70-10-02, Table 2.
e) Close the unit.
3. Removal-installation of a thermocouple (Figure 203)
A. Purpose
Replacement of a faulty thermocouple.
B. Means required
(1) Possible spares
203 3 Thermocouple 77-21 1 8
203 4 Stop ring 77-21 1 7
205 8 Clamp 71-51 1 39
205 - Clamp 71-51 1 40
(2) Products
- Graphite mineral vaseline as per standard AIR 4247.

- Lockwire.
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C. Removal
(1) Perform preliminary steps.
(2) Disconnect the thermocouple (3) inside the unit.
(3) Extract the stop ring (4) attaching the sheath end fitting (5) to the unit.
(4) Unscrew and remove the clamp(s) that hold the thermocouples together.
D. Installation
(1) Install the sheath end fitting (5) in the unit and secure it in position by installing the stop ring
(4).
(2) Connect the thermocouple (3) and the output cable by installing lugs, flat washers, tooth
washers and nuts on the corresponding terminals.
Tighten to the torque load given in chapter 70-10-02, table 2.
Figure 203 – Removal-installation of a thermocouple
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(3) Ensure for absence of contact between the lugs and the metallic parts of the unit (visual
inspection or using a multimeter).
(4) Install the unit cover and close it by turning the lock a quarter-turn.
(5) Coat the exhaust diffuser boss with graphite mineral vaseline.
(6) Install the probe in the boss, POSITION THE PROBE ensuring correct positioning of key (2)
in the notches (1) of the boss.
(7) Screw in and tighten to the torque load given in chapter 70-10-02, table 2, then lock with
stainless steel lockwire.
4. Removal-installation of pyrometric harness
A. Purpose
B. Means required
(1) Spares
204 5 Connection unit 77-21 1 1

assembly
(2) Products
- Lockwire.
- Graphite mineral vaseline as per standard AIR 4247.
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D. Removal
(1) Disconnection of unit (Figure 204)
a) Using a screwdriver, turn lock (1) by a quarter turn and remove the cover (2) with the
lock.
b) Unscrew the two nuts (3) (recover washers), take out the conductors (9) from the power
supply cable (6) of the connection terminals (4), screw in the two nuts.
c) Unscrew the ring (8) by a few turns until stick (7) slides; take out the stick from the unit
with the power supply cable.
d) Remove stick (7) from the cable (6).
Figure 204 – Disconnection of unit
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(2) Removal of pyrometric harness (Figure 205)
a) Unscrew and remove clamps (8).
b) Unlock and unscrew attachment connectors (5) and remove the thermocouples (6) from
the exhaust diffuser (4).
c) Unscrew the three attaching screws (3) and remove the connection unit (1) along with
the thermocouples.
Figure 205 – Removal-installation of pyrometric harness
E. Installation
(1) Installation of pyrometric hamess (Figure 205)
a) Install the new connection unit (1) on support (2) and screw in and tighten the three
attaching screws (3).
b) Coat the exhaust diffuser bosses (7) with graphite mineral vaseline.
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c) Install each of the thermocouple probes (6) in its corresponding boss (7) as follows:
- Position probe (6) ensuring correct positioning of the key in the notch of boss (7).
- Screw in connector (5) while maintaining the probe (6) pressed. Tighten to the torque
load indicated in table 2 of chapter 70-10-02.
d) Install clamps (8) and tighten moderately.
(2) Connection of unit (Figure 204)
a) Install stick (7) on the power supply cable (6).
b) Insert the conductors (9) of power supply cable (6) and the stick (7) into the
corresponding orifice of the unit.
c) Screw in ring (8) until the stick is immobilized.
d) Install conductor lugs on terminals (4), screw in and tighten the self-locking nuts by
aligning the red marks on the cover and the lock.
e) Replace the resistance as indicated in the following paragraph.
f) Install the cover (2) on the unit, install the lock (1) in the corresponding orifice of the
cover, lock by aligning the red marks on the cover and the lock.
5. Replacement of homogeneisation resistor (Figure 206)
A. Purpose
- In the event of a faulty resistor.
B. Means required
(1) Spares
206 5 Adjustable resistor 77-21 1 13
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(1) Remove the side covers (See chapter 71-10-01, pages 201 and 202).
(1) Remove the cover (2) by opening the lock (1).
(2) Unscrew and remove the two nuts (3) and washers (4).
(3) Remove the resistor (5).
Figure 206 – Replacement of resistor
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(1) Make sure that the washers (6) are installed.
CAUTION: THE NEW RESISTOR MUST BE CALIBRATED TO THE VALUE GIVEN

IN THE TEST BENCH TEST CERTIFICATE, WHICH IS ATTACHED TO
THE ENGINE LOG BOOK.
(2) Install new calibrated resistor (5).
(3) Install the washers (4) and nuts (3). Tighten moderately.
(4) Install the cover (2) and lock (1).
(1) Install the side covers (see chapter 71-10-01, pages 201 and 202).
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TEMPERATURE T4 INDICATION
THERMAL PROBE
1. General
At the junction point of the Chromel Copper and Alumel Copper, temperature variations of the ambient
air distort measurement of the exhaust gas temperature t4.
To compensate for these variations, a thermal probe measures the temperature of the air around the
connector.
This measurement allows correcting the indication, to obtain a result corresponding to the true value
(t4), at the output of the thermocouple unit.
This is a wound platinum wire thermal probe.
It comes in the form of a rectangular body (4), drilled with two attaching holes. Three conductors (5)
terminated by connection clips (6) allow its use.
Figure 1 – Thermal probe
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3. Operation
The thermal probe is a platinum wire resistor. Its resistivity depends on the temperature.
The 24 V DC current crossing it undergoes current variations which are proportional to those of the
temperature.
Two of the conductors are connected at one end of the resistor. The other conductor is connected to
the other end. The assembly is moulded in resin.
It is set at 100 Ω for 0° C.
Figure 2 – Average characteristic curve of thermal probe
The thermal probe (7) is secured to the side of the front frame (8) of the covering, by two screws (3)
and nuts (1), with a reinforcement plate (2).
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THERMAL PROBE
A. Check attachment of thermal probe.
B. Check attachment of electric power supply conductors.
2. Removal-installation of thermal probe
A. Purpose
- Replacement of thermal probe in the event of operation anomaly.
B. Means required
(1) Spares
201 2 Thermal probe 77-21 2 27
(2) Possible spares
201 6 2 self-locking nuts 77-21 2 30
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(1) Disconnect the electric power supply conductors (4) from the thermal probe.
(2) Unscrew the two self-locking nuts (6), recover their washers (5) and plate (7).
(3) Remove the two screws (1) from the front frame (3), remove the thermal probe (2).
Figure 201 - Removal-installation of thermal probe
E. Check (Figure 201)
(1) Check locking torque of self-locking nuts. Replace them if the torque read does not
correspond with that indicated in chapter 70-10-02.
F. Installation
(1) Insert the two screws (1) in the front frame (3) and install the thermal probe (2) on these
screws.
(2) Install plate (7) on the thermal probe. Screw in and tighten the self-locking nuts (6) fitted with
washers.
(3) Connect electrical conductors (4) on thermal probe.
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EXHAUST
TABLE OF CONTENTS
Exhaust pipe
- Exhaust pipe 78-10-01 1

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EXHAUST
78 1 May 1981
2 Sept. 1995
78-10-01 1 June 1994
201 Sept. 1995

202 Sept. 1991

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EXHAUST
EXHAUST PIPE
1. General
The engine comprises an exhaust pipe, added on the exhaust diffuser. The exhaust pipe is used for
evacuating exhaust gases.
The exhaust pipe consists of three parts assembled by welding. It is in the form of a cylindrical ring (6)
fitted, at the front, with an attachment flange (5) and, at the rear, with a reinforcement ring (7).
The exhaust pipe (8) is maintained on the exhaust diffuser (9) by a clamp (4). This clamp comprises
two assembling segments (1) held by a tightening ring (3) and a quick-fastener (2).
Figure 1 – Nozzle
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EXHAUST PIPE
1. Removal – installation of exhaust pipe
A. Purpose
Removal of the exhaust pipe gives access to the third turbine wheel, enabling either to check
turbine play, or to manually rotate the engine by means of the wheel.
B. Preliminary steps
NOTE: The suction nozzle has only to be removed on some MHs not modified M004 of the N.L
Marine.
Remove the nozzle from the enclosure.
C. Removal (Figure 201)
(1) Unscrew nut (1) tightening the fastening clamp until the flange (3) can be disengaged from
screw (2) by pivoting it around its shaft.
(2) Slightly separate the tightening ring (5) until the segments (6) release the exhaust pipe (4).
Remove the exhaust pipe.
Figure 201 - Removal-installation of nozzle
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D. Installation
Carry out the removal operations in reverse order, referring to chapter 70-20-02 for tightening the
clamp (tightening torque: nut locking torque + 0.1 to 0.3 daN.m).
NOTE: The suction nozzle has only to be removed on some MHs pre-mod. M004 of the N.L
Marine.
Install suction nozzle.
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EXTERNAL OIL SYSTEM
TABLE OF CONTENTS
Accessories
- Oil cooler 79-10-01 1 and 2

Distribution
- Pipes 79-20-01 1
Checks
- General 79-30-00 1
- Oil pressure check:
pressure switches 79-30-01 1 to 3
- Oil temperature check 79-30-02 1 to 3

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EXTERNAL OIL SYSTEM
79 1 Sept. 1991
2 Sept. 1995
79-10-01 1 Dec. 1983

2 May 1981
201 Sept. 1991

202 May 1981
203 Dec. 1983
79-20-01 1 May 1981
79-30-00 1 May 1981
79-30-01 1 Dec. 1983

2 Sept. 1995
3 May 1981
201 Sept. 1991

202 Sept. 1991
203 Sept. 1991
79-30-02 1 Dec. 1983

2 Dec. 1983
3 May 1981
201 Sept. 1991

202 May 1981
203 May 1981
204 May 1981

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ACCESSORIES
OIL COOLER
1. General
The oil is cooled by an oil cooler located on the alternator. The cooling air from the altemator is sucked
in through the oil cooler which cools it.
It consists of two packages (4) separated by pipe grooves (2) and including two attachment flanges (5)
and two inlet and outlet orifice sleeves (3).
3. Operation
Oil enters into one package and goes out from the other, cooled, going through pipe grooves. Air for
cooling flows between these grooves.
The oil cooler has a cooling power of 10 kW.
4. Equipment
The oil inlet and outlet orifices are equipped with components providing pipe connection. The inlet
orifice is fitted with a nipple (7) and an angle connector (6).
At the outlet orifice, a STAUBLI connector (12) is used for quick connection of a pipe for oil sampling.
This connector is screwed on a 3-way connector (10) connected to the oil cooler outlet orifice by a
nipple (8) and a straight connector (9).
The pipe is connected on a nipple (11) screwed on the third orifice of the connector (10).
Several seals (13) ensure tightness.
5. Assembly
The oil cooler (1) is secured to the alternator by ten screws (14).
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Figure 1 – Oil cooler
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OIL COOLER
A. Check cleanliness of oil cooler.
B. Check oil cooler attachment.
C. Check condition and attachment of pipes and tightness of connectors.
2. Removal – installation of oil cooler

GOGGLES.
A. Purpose
- Cleaning of oil cooler.

- Replacement in the event of oil cooler damage.
B. Means required
(1) Possible spares
201 8 Oil cooler 79-11 1 13
201 1 Seal 79-11 1 3
201 10 Seal 79-11 1 12
(2) Products
- Solvent.
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C. Removal
(1) Removal of oil cooler replacement
a) Unscrew the connectors (4) and (15), and remove pipes (5) and (16).
NOTE: These pipes may contain a certain quantity of oil. Therefore, take all
necessary precautions during removal.
b) Unscrew nut of angle connector (3) and remove connector.
c) Unscrew nipple (2); discard seal (1).
d) Unscrew nut of straight union connector (12), remove 3-way connector (13) fitted with
connector (12) and nipple (14).
e) Unscrew nipple (11); discard seal (10).
f) Unscrew the ten attaching screws (6), recover their washers (7), and remove oil cooler
(8).
(2) Removal of oil cooler for cleaning
a) Perform operations a. to f. in paragraph 1. above.
Figure 201 – Removal-installation of oil cooler
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D. Cleaning oil cooler
(1) Using a brush soaked in solvent, clean the oil cooler pipe grooves.
(2) Dry with a blast of dry compressed air.
E. Installation
(1) Install the oil cooler (8) on the alternator (9), screw in the ten attaching screws (6) fitted with
their washers (7) and tighten.
(2) Screw in nipple (11) fitted with its new seal (10), in the outlet orifice of the oil cooler. Tighten.
(3) Install 3-way connector (13), placing the straight union connector (12) on nipple (11). Screw
in and tighten the connector nut.
(4) Screw in nipple (2), fitted with a new seal (1), on the oil cooler inlet orifice. Tighten.
(5) Install the angle connector (3) on the nipple (2), screw in and tighten its nut.
(6) Install pipes (5) and (16), screw in and tighten connectors (4) and (15).
CAUTION: TAKE CAKE WHEN ORIENTING PIPE CONNECTORS.
- Connector (3) for oil inlet to the oil cooler must be slightly oriented to the top.
- Connector (13) for oil outlet from the oil cooler must be slightly oriented to the bottom.
F. Test
(1) Start up the engine and operate it for a few minutes to check for absence of leakage.
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DISTRIBUTION
PIPES
The pipes used with lubrication components are described in chapter 72-80-05.
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CHECK
GENERAL
Since oil is the main element which ensures correct operation of the engine lubrication, cooling), its
specific and permanent check contributes to preserving the engine from most of the incidents which
may occur.
There are two types of checks: periodic and permanent.
- Periodic check allows ensuring quantity and quality of oil (oil level in tank, deposits on filters, fuel
dilution power, etc.).
These checks are described in chapter 72-80.
- Permanent check consists in checking the pressure and temperature of oil during operation.
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CHECKS
OIL PRESSURE CHECK: PRESSURE SWITCHES
1. General
Oil pressure is checked at two different points of the system by two pressure switches. The first check
gives the pressure of the lubrication system and causes instantaneous engine shutdown as soon as, by
accident, the pressure is below a certain limit. The second check gives a signal when the speed
governor enters into operation, since the governor is controlled by an oil system derived from the main
system.
The two pressure switches are similarly built; only the adjustment of the tripping pressure differs.
They comprise a main body (5) closed by a cover (3) and maintained by four screws (1). They each
include an electrical connection (4) and an oil inlet connection (6). An identification plate (2) is riveted
on the cover.
Figure 1 - Pressure switch
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3. Operation of low oil pressure switch
This pressure switch is set such that a pressure below 0.7 bar triggers its switchover.
It is supplied with 24 V DC. The maximum admissible pressure is 8 bars. It is connected to the control
panel by a cable from the monitoring harness.
4. Operation of load pressure switch
The load pressure switch is set such that a pressure below 8 bars triggers its switchover. As regards
the fuel control unit, takeover by the latter starts with a drop of control pressure in the fuel metering
valve control system.
The maximum operating pressure is 8 bars. It is supplied with 24 V DC. It is connected to the control
panel by a cable from the monitoring harness.
5. Equipment (Figure 1)
The oil inlet connections (6) are equipped with components for connecting pressure switches. They are
fitted with a tapped connector (9) on which a nipple (11) is screwed. Tightness is ensured by two seals
(8) and (10).
The two pressure switches (1) and (2) are maintained on the accessory plate (6) of the engine by a
support (4) covered by a rubber profiled section (3) and secured by two screws.

1995
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Figure 2 – Assembly of pressure switches
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PRESSURE SWITCHES

GOGGLES.
1. Removal-installation of pressure switch
A. Purpose
- In the case of operation anomaly.
B. Means required
(1) Spares
Fig. Item Designation IPC Chap Fig. Item
201 4 Seal 77-21 2 4
201 2 Seal 77-21 2 2
(2) Products
- Solvents.
(1) Remove the equipment side cover (see 71-10-01, pages 201 and 202).
(1) Remove the cover (9).
(2) Disconnect the power supply wires and mark them. Remove the packing gland, take out the
rubber sleeve and the cable.
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(3) Disconnect the supply pipe.
(4) Remove the two attaching screws (6) and remove the support (5).
(5) Remove the pressure switch.
NOTE: If the pressure switch is to be replaced, the old pressure switch must be
disassembled to assemble the new one with nipple (1), tapped connector (3)
and new seals (2) and (4).
Figure 201 – Removal – installation of pressure switch
(1) If necessary, assemble the pressure switch (see NOTE above).
(2) Install the pressure switch at the end of the supply pipe. Do not tighten the connector.
(3) Install support (5) and two attaching screws (6). Tighten.
(4) Tighten the supply pipe connector.
(5) Connect the electrical wires (marked). Tighten the attaching nuts moderately.
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(6) Install the rubber sleeve and connector (10). Tighten moderately.
(7) Install the cover (9) and the four attaching screws. Tighten moderately.
(1) Carry out a ground run check. Drain the connector (1) and check the tightness.
(2) Install the side covers (see 71-10-01, pages 200).
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CHECK
OIL TEMPERATURE CHECK
1. General
Measurement of oil temperature determines that of the bearings, where this oil heats and ensures
lubrication and cooling. A normal temperature rise results in excessive or abnormal heating of a
bearing or of the engine in general.
The oil temperature is measured by a probe connected to an indicator located on the control panel.
In the event of oil overheating, with reference to a limit temperature, a thermal switch generates an
electric signal which instantaneously shuts down the engine.
2. Probe (Figure 1)
A. Description
This probe has a resistance which varies as a function of the temperature.
Externally, it consists of a threaded body (3) for attachment, and a bulb (4) which is plunged in the
oil. Two terminals (2) with screws (1) are used for connecting cable conductors from the
monitoring harness, which connects it to the indicator.
Figure 1 - Probe
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B. Operation
Inside the probe, a wire produces an electrical resistance which varies proportionally with the
temperature. This varies the intensity of the 24 V DC current which crosses it. This variation is
transmitted to the indicator. The probe can be used between temperatures of 40 and 120 °C.
3. Thermal switch (Figure 2)
A. Description
This is a twin blade thermal switch.
Externally, it consists of a threaded body (3) for attachment, and a bulb (4) which is plunged in the
oil.
Two terminals (1) with nuts (2) are used for connecting cable conductors from the control panel,
which connects it to the indicator.
B. Operation
The thermal switch cuts off the electric system when the temperature exceeds 90 °C.
Figure 2 – Thermal switch
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The probe (1) and thermal switch (11), each fitted with a tightness O-ring (2), are screwed into a body
(3), in which oil flows. This body is secured to the front frame of the enclosure (12), by a screw (4). It
comprises two orifices fitted with components for connecting two oil inlet ant outlet pipes (see chapter
72-80-05).
In each of these orifices, a straight connector (7) is screwed. An angle connector (8) is screwed into
this straight connector. Tightness of the straight connectors is ensured by an O-ring (5) maintained in a
retaining ring (6). A machined orifice of the body is blanked by plug (10), fitted with a seal (9).
Figure 3 – Assembly
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OIL TEMPERATURE CHECK
A. Check tightness and attachment of probe and thermal switch.
B. Check attachment of electric power supply cables.
C. Check condition and attachment of pipes and tightness of connectors.
D. Check locking with lockwire.

WITH ENGINE OIL. WORK IN A WELL VENTILATED AREA, OIL IS
GOGGLES.
2. Removal – installation of probe (Figure 201)
A. Purpose
B. Means required
(1) Spares
201 3 Probe 77-21 2 10
201 2 Seal 77-21 2 12
- Remove the right side cover.
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D. Removal
(1) Unscrew two screws (4), remove the lugs of conductors (5) from the probe connection
terminals.
(2) Unscrew probe (3). Discard seal (2).
NOTE: The lubrication pipes connected to the body (1) contain a certain quantity of oil.
Take the necessary precautions when removing the probe.
E. Installation
(1) Screw in the new probe (3) fitted with a new seal (2) into the corresponding orifice of the
body (1). Tighten.
(2) Install lugs of the conductors (5) on the probe terminals. Screw in and tighten screws (4).
Figure 201 – Removal – installation of probe
(2) If necessary, top up the oil tank.
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ASTAZOU IV M1
MAINTENANCE MANUAL
3. Removal – installation of thermal switch (Figure 202)
A. Purpose
B. Means required
(1) Spares
202 3 Thermal probe 77-21 2 11
202 2 Seal 77-21 2 12
D. Removal
(1) Unscrew two nuts (4), remove the lugs of conductors (5) from the thermal probe connection
terminals.
(2) Unscrew the thermal probe (3). Discard seal (2).
NOTE: The lubrication pipes connected to the body (1) contain a certain quantity of oil.
Take all necessary precautions when removing the thermal switch.
Figure 202 – Removal – installation of thermal switch
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MAINTENANCE MANUAL
E. Installation
(1) Screw in the new thermal switch (3), fitted with a new seal (2), into the corresponding orifice
of body (1). Tighten.
(2) Install the lugs of conductors (5) on the thermal switch terminals. Screw and tighten the
nuts (4).
Page 204
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
STARTUP
TABLE OF CONTENTS
Setting into rotation
- Starter 80-10-01 1 and 2

Page 1
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
STARTUP
80 1 May 1981
2 Dec. 1983
80-10-01 1 Dec. 1983

2 May 1981
201 May 1981

202 May 1981
203 May 1981
204 May 1981
Page 2
December
by the notice appearing on the information page 80 1983
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
SETTING INTO ROTATION
STARTER
1. General
Cranking of the turboshaft engine during a startup operation or during a ventilation operation is carried
out by an electric starter.
The electric part is of the compound engine type.
It comes in the form of a cylindrical block (6) fitted, at the front, with an attachment flange (8). On the
side and at the rear, two electric connection terminals, fitted with nuts (6), receive the cables from the
startup system which supply the engine. The drive takes place at the front, through a splined shaft (9).
3. Assembly
The engine is driven by means of the accessory drive pinion train, through the relay box (16) on which
the starter (10) is mounted.
The splined shaft of the starter engages in the splines of the relay box (see chapter 72-60-02). An
O-ring (11) ensures tightness. The starter is maintained by a clamp (15) consisting of three fastening
segments (13) and a tightening ring (12), fitted with a quick-fastening system (14). It tops the flanges of
the starter and the relay box.
The highly balancing effect, due to the weight of the starter which is relatively high, is cancelled by a
support (2) which supports the rear of the starter. It is secured, on the starter, by three screws (3) fitted
with spacers (4) and, on the engine; by two screws (1) for attaching the turbine casing to the air inlet
casing.
Page 1
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
Figure 1 – Starter
Page 2
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
STARTER
A. Check attachment of starter and locking of fastening clamp.
B. Check attachment of starter electric power supply cables.
2. Removal – Installation of starter
A. Purpose
- Replacement of starter in the event of operating anomaly.

- Removal of relay box.
B. Means required
(1) Spares
202 1 O-ring 80-11 1 4
(2) Possible spares
202 5 Starter 80-11 1 1
(3) Products

- Lockwire.
(1) Drain the torque limiter casing.
Page 201
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ASTAZOU IV M1
MAINTENANCE MANUAL
(1) Removal of equipped starter
a) Unscrew nuts (9), remove the lugs from electric power supply cables (8) of the starter
terminals (10).
b) Unscrew two attachment screws (12) of support (11).
c) While maintaining the starter (relatively high weight), unlock and unscrew the fastening
clamp tightening screw (6) of the starter until the flange (5) can be cleared from the
catch lock (4) by pivoting the screw around its axis.
d) Slightly move away the tightening ring (1) and the segments (1), release the flange of
the starter. Separate the starter from the clamp and the relay box (3) by pulling parallel
to the engine shaft. Remove the starter (7).
Figure 201 – Removal – installation of starter
Page 202
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
(2) Removal of components (Figure 202)
a) Remove O-ring (1) from starter and discard O-ring.
b) Unscrew the three attaching screws (3), remove the support (2) and the spacer (4)
NOTE: This operation is not required if the relay box is to be removed.
Figure 202 – Removal-Installation of starter components
E. Installation
(1) Installation of starter components (Figure 202)
a) Install a spacer (4) on one of the drillings for attaching the starter (5), install the support
on the spacer, screw a screw (3) into the starter, taking care that it crosses the support
and the spacer.
b) Carry out the same operation with the two other screws. Only tighten when all the
screws are in place.
c) Install a new O-ring (1), coated with vaseline on the starter.
Page 203
TURBOMECA
ASTAZOU IV M1
MAINTENANCE MANUAL
(2) Installation of equipped starter (Figure 201)
a) Install the starter (7), positioning its drive shaft in front of the opening in the relay box
(3). Engage the shaft in the relay box, install the fastening clamp on the flanges of the
relay box and of the starter.
b) Install, screw in and tighten two screws (12).
c) Tighten the clamp as indicated in chapter 70-20-02 (tightening torque = nut locking
torque + 0.3 to 0.4 daN.m). Lock with lockwire.
d) Install the lugs of the electric power supply cables (8), on the terminals (10) of the
starter, with the cable marked “D+” on the terminal located on the starter side. Screw in
and tighten nuts (9).
(2) Install side cover.
Page 204

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TURBOSHAFT ENGINE

Original issue: December 1980

64511 BORDES CEDEX - FRANCE - Tel.: 05.59.12.50.00 - Telex: 560928

Designation Chapter/Section Pages

- Presentation of manual 00-00-01 1 to 3

The information included in this manual is covered

LIST OF EFFECTIVE PAGES

Chapter/Section Page Date Chapter/Section Page Date

00-00-01 1 May 1981

00-00-02 1 Sept. 1991

The information included in this manual is covered

- Description and operation Pages 1 to 100

Maintenance operations (subdivided if necessary):

- Routine maintenance Pages 301 to 400

- General Pages 101 to 110

Two types of operations are implemented during turboshaft engine operation.

A. Mandatory maintenance operations

CAUTION: ADJUSTMENTS GIVEN IN THIS MANUAL MUST ONLY BE

GENERAL ........................................................................................................................... 00-00

Presentation of Manual ............................................................................................... 00-00-01

HEALTH - SAFETY.................................................................................................................... 01-00

Hazards caused by electric currents........................................................................... 01-00-01

GENERAL ........................................................................................................................... 05-00

INSPECTION ...................................................................................................................... 05-10

Implementation inspection .......................................................................................... 05-10-01

Periodic inspections.................................................................................................... 05-10-02

GENERAL .......................................................................................................................... 26-00

General ....................................................................................................................... 26-00-01

Treatment after accidental triggering of an extinguisher on cold engine

GENERAL ........................................................................................................................... 70-00

General instructions .................................................................................................... 70-00-01

STANDARD ASSEMBLY ................................................................................................... 70-20

General ....................................................................................................................... 70-20-00

O-rings ........................................................................................................................ 70-20-01

Miscellaneous and touch-ups ..................................................................................... 70-30-01

TURBO-GENERATOR UNIT ..................................................................................................... 71

GENERAL ........................................................................................................................... 71-00

Turbo-generator unit ................................................................................................... 71-00-01

ENCLOSURE ..................................................................................................................... 71-10

Package ...................................................................................................................... 71-10-01

Attachments and lifting ............................................................................................... 71-20-01

Structure assembly ..................................................................................................... 71-40-01

Electrical harnesses.................................................................................................... 71-50-01

Equipment ................................................................................................................... 71-70-01

GENERAL ........................................................................................................................... 72-00

Composition of engine ................................................................................................ 72-00-01

Connection casing....................................................................................................... 72-10-01

Reduction gearbox...................................................................................................... 72-10-03

General ....................................................................................................................... 72-20-00

Air inlet casing ........................................................................................................... 72-20-01

General ....................................................................................................................... 72-30-00

Compressor counter-casing ....................................................................................... 72-30-01

Centrifugal compressor ............................................................................................... 72-30-03

Diffuser bearing .......................................................................................................... 72-50-03

General ....................................................................................................................... 72-60-00

Pinion system ............................................................................................................. 72-60-01

General ....................................................................................................................... 72-80-00

System operation ....................................................................................................... 72-80-01