HAL Tejas

 

In 1969, the Indian government accepted the recommendation by its Aeronautics Committee that Hindustan Aeronautics Limited (HAL) should design and develop a fighter aircraft around a proven engine. Based on a 'Tactical Air Support Aircraft' ASR markedly similar to that for the Marut,^[18] HAL completed design studies in 1975, but the project fell through due to inability to procure the selected "proven engine" from a foreign manufacturer and the IAF's requirement for an air superiority fighter with secondary air support and interdiction capability remained unfulfilled.^[19]

In 1983, IAF realised the need for an Indian combat aircraft for two primary purposes. The principal and most obvious goal was to replace India's ageing MiG-21 fighters, which had been the mainstay of the IAF since the 1970s. The "Long Term Re-Equipment Plan 1981" noted that the MiG-21s would be approaching the end of their service lives by the mid-1990s, and that by 1995, the IAF would lack 40 percent of the aircraft needed to fill its projected force structure requirements.^[20] The LCA programme's other main objective was an across-the-board advancement of India's domestic aerospace industry.^[21] The value of the aerospace "self-reliance" initiative is not simply the aircraft's production, but also the building of a local industry capable of creating state-of-the-art products with commercial spin-offs for a global market.^[22]

In 1984, the Indian government chose to establish the Aeronautical Development Agency (ADA) to manage the LCA programme. While the Tejas is often described as a product of Hindustan Aeronautics Limited (HAL), responsibility for its development belongs to ADA, a national consortium of over 100 defence laboratories, industrial organisations, and academic institutions with HAL being the principal contractor.^[23] The government's "self-reliance" goals for the LCA included the three most sophisticated and challenging systems: the fly-by-wire (FBW) flight control system (FCS), multi-mode pulse-doppler radar, and afterburning turbofan engine.^[24]

The IAF's Air Staff Requirement for the LCA were not finalised until October 1985. This delay rendered moot the original schedule which called for first flight in April 1990 and service entry in 1995; however, it also gave the ADA time to better marshal national R&D and industrial resources, recruit personnel, create infrastructure, and to gain a clearer perspective of which advanced technologies could be developed locally and which would need to be imported.^[19][25]

Project definition commenced in October 1987 with France's Dassault-Breguet Aviation as consultants. Dassault-Breguet were to assist in the design and systems integration of the aircraft, with 30 top-flight engineers reported to have flown to India to act as technical advisers to IADA, in exchange for $100m / ₹560 crore (equivalent to ₹70 billion or US$840 million in 2023), this phase was completed in September 1988.^[25][26]

 

A review committee was formed in May 1989, which reported that infrastructure, facilities and technologies in India had advanced sufficiently in most areas and that the project could be undertaken.^[27] A two-stage full-scale engineering development (FSED) process was opted for.^[20][27] In 1990, the design was finalised using the "control configured vehicle" concept to define a small tailless delta winged aircraft with relaxed static stability (RSS) for enhanced manoeuvrability.^[7][28][27]

Phase 1 commenced in April 1993,^[20] and focused on "proof of concept" and comprised the design development and testing (DDT) of two technology demonstrator aircraft which were named as TD-1 and TD-2. This would be followed by the production of two prototype vehicles (PV-1 and PV-2), TD-1 finally flew on 4 January 2001.^[27] FSED Programme Phase-I was successfully completed in March 2004 and cost ₹2,188 crore.^[20]

The relaxed static stability (RSS) was an ambitious requirement. In 1988, Dassault had offered an analogue flight control system (FCS), but the ADA recognised that digital FCSs would supplant it.^[24] First flying in 1974, the General Dynamics F-16 was the first production aircraft designed to be slightly aerodynamically unstable to improve manoeuvrability.^[29]

In 1992, the LCA National Control Law (CLAW) team was set up by the National Aeronautics Laboratory to develop India's own state of the art fly-by-wire FCS for the Tejas.^[30][31] In 1998, Lockheed Martin's involvement was terminated due to a US embargo in response to India's second nuclear tests in May of that year.^[32][33]

Another critical technology is the multi-mode radar (MMR). The Ericsson/Ferranti PS-05/A I/J-band multi-function radar was initially intended to be used,^[34] and also used on Saab's JAS 39 Gripen. However, after examining other radars in the early 1990s, the Defence Research and Development Organisation (DRDO) became confident that local development was possible. HAL's Hyderabad division and the Electronics and Radar Development Establishment (LRDE) were selected to jointly lead the MMR programme, and work commenced in 1997.^[35] The DRDO's Centre for Airborne System (CABS) is responsible for the MMR's test programme. Between 1996 and 1997, CABS converted the surviving HAL/HS-748M Airborne Surveillance Post (ASP) into a testbed for the LCA's avionics and radar.^[36]

The NAL's CLAW team completed integration of the flight control laws with the FCS software performing flawlessly for over 50 hours of pilot testing on TD-1, resulting in the aircraft being cleared for flight in January 2001. The automatic flight control system (AFCS) has been praised by all test pilots.^[37] Phase 2 commenced in November 2001,^[20] and consisted of the manufacturing of three more prototype vehicles (PV-3, PV-4 and PV-5), leading to the development of the final version that would join the air force and the navy and 8 Limited Series Production (LSP) aircraft, and establishment of infrastructure for producing 8 aircraft per year.^[27] The phase cost ₹3,301.78 crore, and an additional amount of ₹2,475.78 crore was given for induction into Indian Air Force by obtaining IOC and FOC. The total cost for development of Tejas (including PDP, Phase 1 and Phase 2) was ₹7,965.56 crore as of August 2013.^[20]

By mid-2002, the MMR had reported suffered major delays and cost escalations. By early 2005, only the air-to-air look-up and look-down modes — two basic modes — were confirmed to have been successfully tested. In May 2006, it was revealed that the performance of several modes being tested "fell short of expectations."^[38] As a result, the ADA was reduced to running weaponisation tests with a weapon delivery pod, which is not a primary sensor, leaving critical tests on hold. According to test reports, there was a serious compatibility issue between the radar and the LRDE's advanced signal processor module (SPM). Acquisition of an "off-the-shelf" foreign radar is an interim option being considered.^[35][39][40]

Of the five critical technologies the ADA identified at the beginning of the programme as required to design and build a new fighter, two have been successful: the development and manufacture of carbon-fibre composite (CFC) structures and skins, and a modern glass cockpit. ADA has a profitable commercial spin-off in its Autolay integrated automated software for designing 3-D laminated composite elements (which has been licensed to both Airbus and Infosys).^[24] By 2008, 70% of the LCA's components were being manufactured in India, the dependence on imported components was stated to be progressively reduced over time. However, problems were encountered with the other three key technology initiatives.^[41] For example, the intended engine, the GTRE GTX-35VS Kaveri,^[42] had to be replaced with an off-the-shelf foreign engine, the General Electric F404.

Kota Harinarayana was the original Programme Director and Chief Designer for the Tejas Programme.^[43][44]

On 26 February 2016, Defence Minister Manohar Parrikar said in the Lok Sabha that the Indian Air Force would accept 3-4 Tejas (IOC version) that year and eventually stand up a total of 8 squadrons within 8 years. He also said, "We are also in the process of approving the second line of manufacturing to the HAL so that they can produce 16 aircraft per year."^[45] In October 2015, IAF Air Chief Marshal Arup Raha confirmed for the that the air force plans to order 123 (six squadrons) of Tejas Mark 1, triple the 40 aircraft it had previously committed to buying. Later it was declared that those 83 additional Tejas ordered to be the upgraded Mark 1A version.^[16] On 7 November 2016, Parrikar approved procurement of 83 Tejas for the IAF, at a cost of ₹50,025 crore (US$6 billion).^[46] The order for those is expected to be placed by the end of 2019, after the unit price was negotiated between ₹250-₹275 crores (around $40 million) per unit.^[47] By March 2020, the HAL, hopes to expand its production capacity to at least a squadron (16+) of aircraft every year.^[48]

In 2018, IAF formally committed to inducting a total of 324 Tejas aircraft of all versions, if HAL and Aeronautical Development Agency (ADA) can deliver a quality Tejas Mark 2 in time.^[49]

 

 

In March 2005, the IAF placed an order for 20 aircraft, with a similar purchase of another 20 aircraft to follow. All 40 were to be equipped with the F404-GE-IN20 engine.^[50][51] In December 2006, a 14-member "LCA Induction Team" was formed at Bangalore to prepare the Tejas and assist with its introduction into service.^[52]

On 25 April 2007, the first Limited Series Production (LSP-1) Tejas performed its maiden flight, achieving a speed of Mach 1.1 (1,350 km/h; 837 mph).^[25] The Tejas completed 1,000 test flights and over 530 hours of flight testing by 22 January 2009.^[25][53] In 2009, a Tejas achieved a speed of over 1,350 kilometres per hour (840 mph) during sea level flight trials at INS Hansa, Goa.^[25][54]

On 16 June 2008 LSP-2 made its first flight^[25] followed by the first flight of the trainer variant in November 2009.^[55] On 23 April 2010, LSP-3 flew with a hybrid version of the Elta EL/M-2032 multi-mode radar;^[25][56] in June 2010, LSP-4 made its maiden flight in an IAF Initial Operating Clearance (IOC) configuration.^[25][57] By June 2010, the Tejas had completed the second phase of hot weather trials in an IOC configuration with the weapons system and sensors integrated.^[58] Sea trials were also being carried out.^[59] On 19 November 2010, LSP-5 with IOC standard equipment started flight trials.^[60]

In December 2009, the government sanctioned ₹8,000 crore to begin production of the fighter for the Indian Air Force and Indian Navy. The Indian Navy has a requirement for 50 Tejas aircraft and the first prototype, NP-1 was rolled out in July 2010.^[61] IAF ordered 20 additional Tejas fighters after the defence acquisition council cleared the plan.^[62] In December 2014 the LCA Navy successfully conducted ski-jump trials at SBTF Goa. The navy variant has a special flight control law mode. It controls a hands-free take-off, which reduces the pilot workload, as the ramp launches the aircraft on an upward flight path.^[63][64]

In November 2010, it was reported that the Tejas Mk 1 reportedly fell short of the relaxed Air Staff Requirements stipulated for limited series production (LSP) aircraft. The areas that did not meet requirements were power to weight ratio, sustained turning rate, maximum speeds at low altitudes, AoA range, and weapon delivery profiles; the extent of the deficiencies was classified.^[65]

On 9 March 2012, LSP-7 took to its maiden flight from HAL airport.^[25] The Naval LCA made its first flight, almost two years after being rolled out, on 27 April 2012.^[66]

In September 2011, weapons tests, including bombing trials, began at Pokhran range, to be followed by missile trials at Goa.^[67] On 27 June 2012, three Tejas (LSP 2, 3 and 5) aircraft completed bombing runs in the desert of Rajasthan, using precision laser-guided 1,000 lb bombs and unguided bombs.^[68] The Tejas had completed 1,941 flights by July 2012.^[69]

In the later half of 2012, the Tejas was grounded for over three months due to a serious safety issue which arose with the introduction of a new pilots' helmet, which protruded above the ejection seat. There was concern that, during an ejection, the helmet would strike the canopy before the canopy was released. Flight tests resumed in November 2012 after the ejection system had been modified.^[70] LSP 8 had a successful maiden test flight on 31 March 2013,^[71] and the programme had completed 2,418 test flights by 27 November 2013.^[69][72] On 31 March 2013, LSP-8 took to its maiden flight from HAL airport.^[25] On 8 November 2014, PV-6(KH-T2010), a trainer variant, completed its first test flight.^[73]

Out of a total of 35 major avionics components and line-replaceable units (LRUs), only three involve foreign systems.^[74] These are the multi-function displays (MFDs) by Sextant (France) and Elbit (Israel),^[75] the helmet-mounted display and sight (HMDS) cueing system by Elbit,^[75] and the laser pod supplied by Rafael (Israel).^[76] Production aircraft are expected to have MFDs from Indian suppliers. A few important items of equipment (such as the Martin-Baker ejection seat) have been imported.^[74] As a consequence of the embargo imposed on India after its nuclear weapons tests in May 1998, many items originally planned to be imported were instead developed locally; these sanctions contributed to the prolonged delays suffered by the LCA.^[74]

Indian test pilots have praised Tejas' high-speed handling and say the Tejas is the IAF's most "pilot friendly" fighter.^[77][78] Gp. Captain Samrath Dhankhar of the Indian air force, the commanding officer of its 45 Sqn “The Flying Daggers” said about Tejas that it responds to pilot inputs in the entire flight envelope very well, with no need to be at certain speeds to get the maximum out of it.^[79]

A two-seater naval variant of Tejas successfully completed its first arrested landing on September 13, 2019 at the Shore Based Test Facility (SBTF) in Goa. Once the aircraft completes several successful trials on the SBTF, it will demonstrate a landing on the aircraft carrier INS Vikramaditya.^[80][81]

On 10 January 2011, IOC, allowing IAF pilots to fly the Tejas, was awarded by Defence Minister A K Antony to Chief of Air Staff Air Chief Marshal P V Naik.^[82] The IAF raised the first squadron in Bangalore to iron out issues with ADA and HAL, and eventually based these fighters at Sulur Air Force Station, Coimbatore in the southern state of Tamil Nadu. The No. 45 Squadron IAF "Flying Daggers" was the first to get their MiG-21s replaced by Tejas aircraft at the base.^[83] Tejas' Final Operational Clearance (FOC) was repeatedly delayed since 2011.^[84][85][86]

HAL was instructed by the Indian government to strictly adhere to deadlines to ensure Initial Operational Clearance-II by the end of 2013 and Final Operational Clearance (FOC) by the end of 2014.^[87] On 20 December 2013, IOC-II was issued, after which the aircraft was cleared to be flown by regular IAF pilots and begin induction into squadron service. To fulfill the IOC-II standard, the aircraft was certified to carry close to three tons of weapons including laser-guided 500 kg bombs and short-range R-73 missiles,^[88][89] reach top speeds of 1,350 km per hour, withstand turns up to 7 g, reach angle of attack of 24 degrees (from 17 degrees initially), and have an operational radius of 400–500 km.^[90][91]

To obtain FOC, the fighter had to be certified for six more criteria. Integration of Derby and Python BVR missiles weighing 150 kg, with a range of 70 km, as well as the Gryazev-Shipunov GSh-23 twin-barreled 23 mm autocannon fired in mid-air. An air-to-air refuelling probe supplied by Cobham will be added to the FOC variants. The angle of attack has been increased from 24° to 26°,^[92] the braking system enhanced, and the existing nose cone radome made of composites replaced by a quartz model in a bid to increase the current radar range of 45–50 km to more than 80 km. Tejas's prototypes have been tested to withstand g-forces of up to 8.5 g, as required of the FOC variants.^[92] To expand the flight envelope to meet service requirements, the programme enlisted assistance from EADS.^[93]

These modifications were originally expected to be completed within 15 months of IOC-II, but realistically took far longer.^[94][95]

The Final Operational Clearance (FOC) campaign began in December 2013, with three aircraft from Tejas flight-line successfully completing advanced weapon trials. The campaign was held in Jamnagar. New weapons were integrated on the aircraft.^[96] As part of the FOC, the aircraft is being readied for all-weather trials in Bangalore and in Gwalior. Tejas took its maiden flight in January 2001, and by December 2013, it had completed 2,587 sorties covering over 1,750 hours.^[96] In July 2014, the FOC was pushed back as six or more aircraft were needed for testing and only one had been produced then.^[97] Tejas received IOC-II clearance on 17 January 2015.^[98]

In February 2016, LSP-7 test-fired the BVRAAM Derby missile on a BNG (Ballistic Non Guided) mode in Jamnagar as part of its scheduled weapon trials. These weapon trials are part of the Final Operational Clearance (FOC) mandate. It was the 169th flight of LSP-7 and was piloted by Group Capt Rangachari of National Flight Test Centre. The aircraft is also scheduled to fire a Close Combat Missile (CCM) Python-5 as part of the FOC trials. The LSP-7 along with LSP-4 were part of Indian flying assets at the Bahrain International Air Show (BIAS-2016).^[99]

On 12 May 2017, Tejas successfully demonstrated an Air-to-Air Beyond Visual Range (BVR) missile firing capability by releasing Derby Air-to-Air BVR missile in RADAR guided mode. The missile launch was performed in lock-on after launch mode.^[100] The missile destroyed its manoeuvrable aerial target with pinpoint precision at the Interim Test Range, Chandipur in Odisha.^[101]

In November 2017, it was reported that the Indian Air Force told the government that the Tejas alone is inadequate for the single-engined fighter program with insufficient flight endurance, smaller payload capacity, increased maintenance hours, etc. compared to larger medium combat aircraft contending in the Indian MRCA competition and may augment them, but cannot be an alternative.^[102] HAL's chief rejected the criticisms and called the Tejas a world class fighter jet that can fill its defined role. He also mentioned that minimum life span of Tejas is 30 years which can be extended.^[103] HAL CMD T Suvarna Raju also stated that HAL delivered five Tejas as of 19 November 2017, which have made more than 600 flights.^[104]

In February 2018, refuelling of Tejas with the engine running—known as "hot refuelling"—was carried out. Hot refuelling capability is one of the requirements for Tejas Mk 1A and is expected to shorten the turnaround time between sorties.^[105]

In August 2018, the naval variant of the Tejas conducted its first "taxi-in" engagement on a naval platform in Goa to prove its hook-arrester system. The Indian Defence Minister, Nirmala Sitharaman's backing of the Tejas programme allowed the restarting of tests and gave its naval variant a fresh lease on life.^[106][107]

In September 2018, Tejas successfully completed the trials for mid air refuelling, which is one of the key items required for the aircraft to obtain FOC.^[108] In January 2019, HAL received permission from CEMILAC to start production of FOC standard Tejas, despite the certification not being awarded yet.^[109]

On 20 February 2019, during Aero India 2019, Final Operational Clearance (FOC) was formally awarded to Tejas,^[110] but the aerial firing trials of its Russian 23mm GSH gun pod was delinked from it due to persisting vibration issues, to be finetuned later on as the ground trials were already completed.^[111]

In May 2015, the Mark 1 aircraft was criticised by the Comptroller and Auditor General of India (CAG) for not meeting IAF requirements, such as a lack of a capable tandem-seated trainer aircraft, electronic warfare capabilities, performance shortcomings of Radar Warning Receiver or Missile approach warning system, weight and cost increases, limited internal fuel capacity, non-compliance of fuel system protection, inadequte forward-facing pilot protection, and performance shortfalls due to underpowered engine.^[112] Most of these issues are to be addressed in the upcoming interim upgrade called Mark 1A and subsequent advanced version Mark 2.

It was reported that IAF agreed to accept 40 aircraft even though the CAG had found serious operational shortfalls, including engine thrust, overweight and pilot protection in front against 7.62 mm rifle calibre rounds. The IAF agreed to accept the initial Tejas aircraft with some deficiencies to keep the programme going.^[113] IAF had initially ruled out further acquisition of Tejas Mk 1 until Mk 2 was ready.^[114] In 2015, the ADA, DRDO and HAL proposed a more advanced Tejas Mk 1A version; as an improved stop-gap to keep production running as Mark 2 was delayed.^[115][116] Following an approval from Defence Acquisition Council for 83 Tejas Mk 1A, HAL invited global bids for AESA radar and ECM pods in December 2016.^[117][118] In December 2018, it was reported that HAL had selected Elta's EL/M-2052 AESA radar and EL/L-8222 ECM pod.^[119]

It is to have changes to the ballast and landing gear to reduce its weight by several hundred kilograms (up to 1,000 kg) and modifications in the shape of canopy, wings, nose-cone, new supersonic drop tank and even redesigned pylons to ensure enhanced aerodynamic performance and 6% reduction in drag,^[92] along with even lower radar cross-section than the publicly available figure of 0.5 m².^[120] Another major improvement in Mark 1A is its higher maintainability,^[121] while hot-refueling and aerial-refueling have both been already demonstrated in prototypes and are to be available features from all FOC standard Tejas. Mark 1A is also expected to use the indigenous Uttam AESA radar,^[120] already installed and being tested on Tejas LSP-2.^[122] Other than that, the design is capable of carrying dual-rack pylons and external Self Protection Jammer on its wing stations.^[92] Also the avionics and sensor package has undergone deep upgradation for Mark 1A, it will feature a new indigenous all-glass cockpit.^[123]

On 20 December 2017, IAF initiated a tender to buy 83 Mark 1A worth 33,200 crore from HAL.^[124] However, with HAL quoting a price of ₹463 crore (US$55 million) per unit, substantially higher than the Mark 1, the Defence Minister Nirmala Sitharaman announced in July 2018 that a committee to look into the cost of the Mark 1A, along with other products manufactured by defence Public Sector Undertakings. The committee, headed by the Defence Ministry's Director of Costs, had been given 60 days time to review the cost of the Mk 1A.^[125] HAL agreed to lower the unit price to between ₹250-₹275 crore (US$33 million) for 73 Mark 1A and 10 Mark 1 trainer jets bringing the value to about Rs 22,825 crores. However this new deal would exclude all maintenance and logistical equipments.^[47] Pricing of the LCA Tejas Mark 1A, which was under discussion with the costing committee has been finalised on 3rd September, 2019 in a meeting with the Secretary of Defence Production, while a separate negotiation for the support package brought the total cost of the deal to ₹45,000 crore (US$5.4 billion). Signing of the contract for the aircraft will happen by December 2019 or January 2020, the first Tejas Mark 1A is expected to be delivered before 2023, 36 months after signing the contract.^[126]

To meet the IAF’s air staff qualitative requirements (ASQR), ADA had to make substantial changes to the basic Mk1/Mk1A airframe to improve payload and performance in the more advanced upgrade called Tejas Mark 2. Initially they planned to simply elongate the Mark1 with a 0.5 m fuselage plug to hold more fuel, while fitting a more powerful General Electric F414-GE-INS6 engine with 64-98 kN of thrust.^[127][128] After further refinement of the design it was decided to bring in further modifications like a new bulged canopy, altered shape of the aft bottom of fuselage, wing-tip pylons, optimised air-intakes and most notably, a pair of close-coupled canards added just behind the canopy. The fuselage has been widened at the centre to make room for more fuel, giving the final design a slightly increased wingspan from 8.2 to 8.5 metres. These are claimed to have brought 20% improvement in its transonic acceleration, while lowering both transonic and supersonic drag. The canards improve its maneuverability and performance at high angle of attacks.^[92]

Although with increased T/W ratio, the new aircraft design is quite a bit longer (14.65 m (48.1 ft)) and heavier (7000 kg) than original light combat aircraft or LCA Tejas. So the new design unveiled in Aero India 2019 was dubbed as "Medium Weight Fighter" or MWF.^[129] Mark 2 is also to feature the Uttam AESA radar, an indigenous on-board oxygen generation system, and a built-in integrated electro-optic electronic warfare suite among other improvements to avionics.^[130] It will have an infra-red search and track (IRST) system and a missile approach warning system (MAWS).^[131] An increase in payload capacity to 6,500 kg (14,300 lb) and increased number of weapons stations from 7 to 11, will allow the MWF to carry more weapons. The chief of ADA confirmed the several Radar cross-section (RCS) reduction measures from HAL AMCA design, India's Fifth-generation jet fighter under development alongside Tejas series, will be incorporated in the Tejas Mark 2. It will reduce electromagnetic and infrared signatures of the aircraft, with use of carbon and thermoplastic composites at the frontal section of the MWF along with radiation-absorbent material (RAM) coating developed for the AMCA program.^[132]

Although sanctioned in November 2009, a delay in procurement of the American engines pushed back the initiation of development of Tejas Mark 2 till 2013. It is on track and expected to have its first flight by 2023.^[133]

In December 2016, the Indian Navy announced that the naval variant of the fighter is overweight, and they will look for other alternatives.^[134][135] The Indian Navy eventually issued an RFI for 57 naval multirole fighters.^[136] However despite rejecting the Tejas initially for being overweight, the Navy restarted testing with the NP-2 (Naval Prototype 2) in August 2018, with the first mid-air refueling being held in September 2018.^[48] Presently a Mark 2 version is being developed for the Navy, which has significant differences compared to the Air Force version. With a wingspan of 8.9 m, leading-edge extension (levcons) and tailplanes instead of canards, its design has taken a completely separate path.^[137]

The Tejas is a single-engine multirole fighter which features a tailless, compound delta wing and is designed with "relaxed static stability" for enhanced manoeuvrability. Originally intended to serve as an air superiority aircraft with a secondary ground-attack role, its flexibility permits a variety of guided air-to-surface and anti-shipping weapons to be integrated for multirole and multimission capabilities.^[138] The tailless, compound-delta planform is designed to be small and lightweight.^[139] This platform also minimises the control surfaces needed (no tailplanes or foreplanes, just a single vertical tailfin), permits carriage of a wider range of external stores, and confers better close-combat, high-speed, and high-alpha performance characteristics than comparable cruciform-wing designs. Extensive wind tunnel testing on scale models and complex computational fluid dynamics analyses have optimised the aerodynamic configuration for minimum supersonic drag, a low wing-loading, and high rates of roll and pitch.^[138]

 

The maximum payload capability of Tejas is 4,000 kg (8,818 lb).^[140] All weapons are carried on one or more of seven hardpoints with total capacity of greater than 4,000 kg: three stations under each wing and one on the under-fuselage centreline. An eighth offset station beneath the port-side intake trunk can carry a variety of pods like FLIR, IRST, laser rangefinder/designator, as can the centreline under-fuselage station and inboard pairs of wing stations.^{[32][141][142]} Auxiliary fuel tanks of 800 and 1,200 litres can be carried under the fuselage to extend range. An aerial refuelling probe on the starboard side of the forward fuselage can further extend range and endurance.^[143] RAFAEL's Derby fire-and-forget missile will serve as the Tejas' initial medium range air-air armament.^[76] The Brahmos NG supersonic cruise missile is being developed for the Tejas.^[144]

Stealth features have been designed into Tejas.^[145] Being small provides an inherent degree of visual stealth, the airframe's high usage of composites (which do not reflect radar waves), a Y-duct inlet which shields the engine compressor face from probing radar waves, and the application of radar-absorbent material (RAM) coatings are intended to minimise its susceptibility to detection and tracking.^[146]

Tejas uses Martin-Baker 16LG zero-zero ejection seat.^[147] DRDO integrated an indigenous CSS, or canopy severance system, in the Tejas which allows the pilot to eject safely.^[148]

 

Tejas is constructed of aluminium-lithium alloys, carbon-fibre composites, and titanium alloys.^[149] Composite materials make up 45% of the airframe by weight and 95% by surface area. Upper and lower wing skins are manufactured from a single piece of carbon-fibre reinforced polymer. Wing spars and ribs are also made out of carbon composites.^[150] The percentage of carbon composites in the airframe by weight rose from 30% in the technology demonstrators to 42% in the prototype vehicles. The construction of elevons, tailfin, rudder, air brakes and landing gear doors use co-cured and co-bonded manufacturing techniques. The radome is made out of Kevlar, while the fin tip is made out of glass-fibre reinforced plastic.^[147] Composite materials are used to make an aircraft lighter compared to an all-metal design, and the LCA's percentage employment of carbon-fibre composites is one of the highest among contemporary aircraft of its class.^[151] Apart from making the plane much lighter, there are also fewer joints or rivets, which increases the aircraft's reliability and lowers its susceptibility to structural fatigue cracks.^[152] The wing and fin of the compound-delta aircraft are of carbon-fibre-reinforced polymer, and were designed to provide a minimum weight structure and to serve as integral fuel tanks.^[153][154] The tailfin is a monolithic honeycomb structure piece, reducing the manufacturing cost by 80% compared to the "subtractive" or "deductive" method, involving the carving out of a block of titanium alloy by a computerised numerically controlled machine. No other manufacturer is known to have made fins out of a single piece.^[155]

The use of composites resulted in a 40% reduction in the total number of parts, including half the number of fasteners required, compared to a metallic frame design. The composite design also helped to avoid about 2,000 holes being drilled into the airframe. Overall, the aircraft's weight is lowered by 21%. While each of these factors can reduce production costs, an additional benefit — and significant cost savings — is realised in the shorter time required to assemble the aircraft — seven months for the LCA as opposed to 11 months using an all-metal airframe.^[156] The wing-shielded, side-mounted air intakes are fixed-geometry with splitter plates.^{[141][unreliable source?]}

In 2001 it was envisaged that the naval variant would have nose droop to provide improved view for carrier landings, and wing leading–edge vortex controllers (LEVCON) to increase lift during approach.^[19] The LEVCONs are control surfaces that extend from the wing-root leading edge and thus afford better low-speed handling for the LCA, which would otherwise be compromised by the increased drag that results from its delta-wing design. The LEVCONs should also increase controllability at high angles of attack (AoA).^[157] The naval Tejas will also have a strengthened spine, a longer and stronger undercarriage, and powered nose wheel steering for deck manoeuvrability.^[76][158] The Tejas trainer variant will have "aerodynamic commonality" with the two-seat naval aircraft design.^[159]

The Tejas has a night vision goggles (NVG)-compatible "glass cockpit", dominated by an CSIR-CSIO domestically-developed head-up display (HUD), three 5 in x 5 in multi-function displays, two Smart Standby Display Units (SSDU), and a "get-you-home" panel providing the pilot with essential flight information in case of an emergency. The displays provide information on key flight systems and controls on a need-to-know basis, along with basic flight and tactical data. The pilot interacts with onboard systems through a multifunctional keyboard and several selection panels. The CSIO-developed HUD, Elbit-furnished DASH helmet-mounted display and sight (HMDS),^[75] and hands-on-throttle-and-stick (HOTAS) controls reduce pilot workload and increase situation awareness by allowing access to navigation and weapon-aiming information with minimal need to spend time "head down" in the cockpit.^[141][146]

The first 20 production Tejas Mk 1 equipped with hybrid version of the EL/M-2032 radar. It features look-up/look-down/shoot-down modes, low/medium/high pulse repetition frequencies (PRF), platform motion compensation, doppler beam-sharpening, moving target indication(MTI), Doppler filtering, constant false alarm rate (CFAR) detection, range-Doppler ambiguity resolution, scan conversion, and online diagnostics to identify faulty processor modules.^[146] The Tejas Mk 1A will be equipped with an improved version of the EL/M-2052 AESA radar being developed jointly by Elta and HAL.^[160]

The electronic warfare suite is designed to enhance combat survivability during deep penetration. The EW suite is developed by the Defence Avionics Research Establishment (DARE) with support from the Defence Electronics Research Laboratory (DLRL). This EW suite, known as Mayavi, includes a radar warning receiver (RWR), Missile Approach Warning (MAW) and a Laser warning receiver (LWR) system, Infrared & Ultraviolet Missile warning sensors, self-protection jammer, chaff, jaff and flares dispenser, an electronic countermeasures (ECM) suite and a towed radar decoy (TRD). In the interim, the Indian Ministry of Defence has revealed that an unspecified number of EW suites had been purchased from Israel's Elisra for the LCA prototypes.^{[161][162][163]}

Tejas is also to be equippable with an infra-red search and track (IRST) sensor, which can detect and track thermal energy emissions.^[164] This system shall be pod-based, additional sensor pods are to include drop tanks for ferry flight/extended range/loitering time, FLIR targeting pod, ECM pods, Flares/Infrared decoys dispenser pod and chaff pod, EO/IR sensor pod, LITENING targeting pods, forward looking infrared (FLIR) sensor, and a laser designator/laser rangefinder, which can be used in various capacities, including reconnaissance, training, or attack.^{[32][141][142]}

 

Since the Tejas is a relaxed static stability design, it is equipped with a quadruplex digital fly-by-wire flight control system to ease pilot handling.^[165] The Tejas aerodynamic configuration is based on a pure delta-wing layout with shoulder-mounted wings. Its control surfaces are all hydraulically actuated. The wing's outer leading edge incorporates three-section slats, while the inboard sections have additional slats to generate vortex lift over the inner wing and high-energy air-flow along the tail fin to enhance high-AoA stability and prevent departure from controlled flight. The wing trailing edge is occupied by two-segment elevons to provide pitch and roll control. The only empennage-mounted control surfaces are the single-piece rudder and two airbrakes located in the upper rear part of the fuselage, one each on either side of the fin.^[166]

 

Early on, it was decided to equip prototype aircraft with the General Electric F404-GE-F2J3 afterburning turbofan engine while a program to develop a domestic powerplant led by the Gas Turbine Research Establishment was launched.^[167] In 1998, after Indian nuclear tests, US sanctions blocked sales of the F404, leading to a greater emphasis on the domestic Kaveri. In 2004, General Electric was awarded a US$105 million contract for 17 uprated F404-GE-IN20 engines to power the eight pre-production LSP aircraft and two naval prototypes;^[168] deliveries began in 2006.^[169] In 2007, a follow-on order for 24 F404-IN20 engines to power the first operational Tejas squadron was issued.^[168]

Cost overruns and delays were encountered in the Kaveri's development.^[170] In mid-2004, the Kaveri failed high-altitude tests in Russia, ruling out it powering the first production Tejas aircraft.^{[169][N 1]} In February 2006, the ADA awarded a contract to French engine company Snecma for technical assistance on the Kaveri.^[171] Using Snecma's new core, an uprated derivative of the Dassault Rafale's M88-2 engine, providing 83–85 kilonewtons (kN) of maximum thrust was being considered by DRDO. The IAF objected that since Snecma already developed the core of the engine, the DRDO will not be participating in any joint development but merely providing Snecma with an 'Indian-made' stamp.^[172] In November 2014, the DRDO was submitting documents to cancel development of Kaveri.^[76]

In 2008, it was announced that an in-production powerplant would have to be selected; this was required to be in the 95 to 100 kilonewton (kN) (21,000–23,000 lbf) range to execute combat manoeuvres with optimal weapons load.^[173][174] After evaluation and acceptance of technical offers for both the Eurojet EJ200 and the General Electric F414, the commercial quotes were compared in detail and GE's F414 was declared as the lowest bidder. The deal covered the purchase of 99 GE F414 engines, an initial batch will be supplied directly by GE and the remainder to be manufactured in India under a technology transfer arrangement.^[175][176] According to the IAF, adopting the new powerplant required a three-to-four years of redesign work.^[177]

 

The formation of the first Tejas-equipped squadron started in July 2011. The Tejas entered service with No. 45 Squadron IAF (Flying Daggers) based at the Aircraft and Systems Testing Establishment at HAL, Bangalore on 1 July 2016 before being moved to Sulur Air Force Station in Coimbatore.^[178] The squadron will initially have four aircraft. The IAF's Aircraft & Systems Testing Establishment will receive four aircraft already built including two development aircraft.^[179]

In June 2017, Hindustan Aeronautics stated that it expects to have delivered 123 Tejas aircraft to the Indian Air Force by 2024–25. HAL outlined a three–pronged approach to accelerate aircraft production. It will build an additional assembly line, reuse the Hawk assembly line, and outsource major components to the private sector.^[180]

The Tejas made its international debut on 21 January 2016, when two aircraft flew in the Bahrain International Air Show.^[181] On 21 November 2016, the Indian Ministry of Defence proposed exporting the Tejas, with preliminary talks taking place with several friendly countries.^[182]

The jet has solicited interest with the United Arab Emirates (UAE) with some discussions made during a visit by UAE Minister of State and Defence Mohammed Ahmed Al Bowardi Al Falacy during a state visit in October 2018 as part of growing defence relations between India and the UAE.^[183] In January 2019, the Royal Malaysian Air Force issued a request for information to HAL regarding the Tejas for their light combat aircraft requirement.^[184]

The Tejas has participated in several military exercises, most recent being Gagan Shakti 2018 and Vayu Shakti 2019, after which the Indian Air Force Air Marshal Birender Singh Dhanoa commended its reliability and precision of air-to-ground payload delivery.^[185] The 45 Squadron of LCA Tejas has successfully flown over 1,500 sorties during trials. During Gagan Shakti 2018 the IAF was able to carry out 6 sorties per day, by all 8 Tejas platforms deployed.^[186] In 2018, HAL Tejas set an impeccable record by completing over 4000 accident-free sorties and test flights, without ever crashing in almost 2 decades.^[187]

 

 

 

Aircraft already built and projected models to be built. Model designations, tail numbers and dates of first flight are shown.

Technology Demonstrators (TD)

• TD-1 (KH2001) – 4 January 2001
• TD-2 (KH2002) – 6 June 2002

Prototype Vehicles (PV)

• PV-1 (KH2003) – 25 November 2003
• PV-2 (KH2004) – 1 December 2005
• PV-3 (KH2005) – 1 December 2006.
• PV-5 (KH-T2009) – 26 November 2009 – Fighter/Trainer Variant
• PV-6 (KH-T2010) – 8 November 2014 – Fighter/Trainer Variant.^[73]

Naval Prototypes (NP)

• NP-1 (KH-T3001) – Two-seat Naval variant for carrier operations. Rolled out in July 2010.^[188] NP-1 made its first flight on 27 April 2012.^[66]
• NP-2 (KH3002) – First flight on 7 February 2015 with ski-jump take-off and arrested landing required in STOBAR carrier.^[189]

Limited Series Production (LSP) aircraft

• LSP-1 (KH2011) – 25 April 2007. This LCA is powered by F404-F2J3 Engine.^[190]
• LSP-2 (KH2012) – 16 June 2008. This is the first LCA fitted with F404-IN20 engine.^[190]
• LSP-3 (KH2013) – 23 April 2010. The first aircraft to have the Hybrid MMR radar^[56] and will be close to the IOC standard.
• LSP-4 (KH2014) – 2 June 2010. The first aircraft that was flown in the configuration that will be delivered to the Indian Air Force.^[57] In addition to the Hybrid MMR, the aircraft flew with a Countermeasure Dispensing System and an identify friend or foe electronic system.^[191]
• LSP-5 (KH2015) – 19 November 2010. IOC standard, with all sensors including night lighting in the cockpit, and an auto-pilot.^[192]
• LSP-6 – Not built.^[193]
• LSP-7 (KH2017) – 9 March 2012. APU intake has been aerodynamically reshaped.
• LSP-8 (KH2018) – First flight trial completed in March 2013. LSP 8 is the version that will go for production.^[71]

• Tejas Mark 1 (IOC standard) - Single-seat variant for Indian Air Force with Initial Operational Clearance. The 45 Squadron (Flying Daggers) operates 16 jets of this variant. Restricted to +7g and lacks BVR capability.^[194][195]
• Tejas Mark 1 (FOC standard) - Single-seat operational variant for Indian Air Force with Final Operational Clearance. All 16 jets to be inducted being BVR capable, with general flight envelope expansion, increased angle of attack, higher g-limit of +8.5g, as well as air-to-air refueling probe and hot-refueling capability.^[196]
• Tejas Trainer - Two-seat operational conversion trainer for the Indian Air Force.
• SPORT - Supersonic Omni-Role Trainer aircraft is a two-seater Lead-in fighter training aircraft being developed from LCA Trainer Mark 1 for export purposes as light fighter.^[197]
• Tejas Mark 1A - In 2015, ADA and HAL proposed the upgraded Tejas Mark 1A as a stop-gap to keep production running until Mark 2 came into production, which was delayed.^[198] It was to include an AESA radar, air-to-air refueling capability, an external ECM pod and improved avionics, aerodynamics, radar signature, ease of maintenance etc.^[199] However, initially HAL quoted a price of ₹463 crore (US$55 million) per unit for Tejas Mark 1A, which IAF the considered too high for a low-end aircraft.^[200] After months of negotiation HAL agreed to lower the unit price to between ₹250-₹275 crore (US$33 million) for 83 Mark 1A and 10 Mark 1 trainer jets bringing the number to about Rs 22,825 crores. However this new deal would exclude all maintenance and support equipment.^[47] Cost Committee of the Defence Ministry determined the final value of the deal to be at ₹45,000 crore (US$5.4 billion) including all installations and logistic packages. Signing of the contract for the aircraft will happen by December 2019 or January 2020, delivery will start by 2023.^[201][202]
• Tejas Mark 1 Navy - Single seat prototypes (NP1 & NP2) powered by F404 engines are used for the initial testing. The Naval variant of Tejas successfully completed testing in Goa during which the short take off (200 meter) from Shore Based Test Facility were carried out along with hot refuelling. The flight test from aircraft carrier is scheduled for 2017.^[203] In December 2016, the navy stated that the aircraft is overweight for carrier operations.^[204]
• Tejas Trainer IN - Two-seat operational conversion trainer for the Indian Navy.
• Tejas Mark 2 Navy - Twin and single-seat carrier-capable variants for the Indian Navy. It will be equipped for carrier operation with ski-jump take-off and arrested landing. It will include strengthened airframe and telescopic landing gear.^[205]
• Tejas Mark 2 - The Tejas Mk 2, also called "Medium Weight Fighter", is to feature the more powerful General Electric F414-GE-INS6 engine with 98 kN of thrust.^{[127][206][110]} In November 2009, Ministry of Defence sanctioned ₹2,431.55 crore (equivalent to ₹61 billion or US$730 million in 2023) for development of Tejas Mk 2, which was expected to be completed by 2018. However, a delay in procurement of engines pushed back the initiation of development till 2013. As of 2018^[update], the project is expected to be completed by 2022. Mk 2 will feature an AESA radar, an on-board oxygen generation system, and a built-in electronic warfare suite among other improvements to avionics.^[130] In January 2019, Air Chief Marshal Birender Singh Dhanoa said that the IAF has committed to procure twelve squadrons of Tejas Mk 2 aircraft.^[207] In Aero India 2019, a model of Tejas Mk 2 with close-coupled canards was displayed. Mk 2 will be slightly larger with a length of 14.6 m (48 ft) and a wingspan of 8.5 m (28 ft). An increase in payload capacity to 6,500 kg (14,300 lb) will allow it to carry more weapons. It will include an infra-red search and track system and a missile approach warning system.^[208]

  India

• Indian Air Force – 40 Tejas Mk 1 ordered, including 16 single-seat aircraft in IOC configuration, a further 16 in FOC configuration and eight twin-seat trainers. IAF has initiated procurement of a further 83 single-seat fighters in Mk 1A configuration and 10 twin-seat trainers with a request for proposal issued to HAL in December 2017.^[209][210] and official order may be placed by late 2019,^[16] induction starts from 2021-22^[211] after delivery of first 40 Mark 1s end in 2020.
  • Sulur Air Force Station
    • No. 45 Squadron (Flying Daggers)^[10]
  • No. 18 Squadron (Flying Bullets) (Proposed)^[212]

 

 

 

Data from tejas.gov.in,^[213] DRDO Techfocus,^[214] and Jane's All the World's Aircraft^[147]

General characteristics

• Crew: 1
• Length: 13.2 m (43 ft 4 in)
• Wingspan: 8.2 m (26 ft 11 in)
• Height: 4.4 m (14 ft 5 in)
• Wing area: 38.4 m² (413 sq ft)
• Empty weight: 6,560 kg (14,462 lb)
• Gross weight: 9,800 kg (21,605 lb)
• Max takeoff weight: 13,300 kg (29,321 lb)
• Fuel capacity: 2,458 kg (5,419 lb) internal; 2 × 1,200 L (260 imp gal; 320 US gal) drop tank inboard, 725 L (159 imp gal; 192 US gal) drop tank under fuselage
• Payload: 5,300 kg (11,700 lb) external stores^[215]
• Powerplant: 1 × General Electric F404-GE-IN20 turbofan, 53.9 kN (12,100 lbf) thrust dry, 90 kN (20,200 lbf) with afterburner^[143][216]

Performance

• Maximum speed: Mach 1.8
• Range: 850 km (528 mi, 459 nmi)
• Combat range: 500 km (310 mi, 270 nmi) with max internal fuel^[217][218]
• Ferry range: 2,100 km (1,300 mi, 1,100 nmi) with drop tanks^[92]
• Service ceiling: 15,000 m (50,000 ft)
• g limits: +8.5/−3.5^[92][219]
• Wing loading: 255.2 kg/m² (52.3 lb/sq ft)
• Thrust/weight: 0.94

Armament

• Hardpoints: 8 (1 × beneath the port-side intake trunk for targeting pods, 6 × under-wing, and 1 × under-fuselage) , with provisions to carry combinations of:
  • Rockets: S-8 rocket pods ^[220]
  • Missiles:
    
    • Air-to-air missiles:
      • Derby^[221]
      • Python-5 ^[222]
      • R-73^[220]
      • Astra(expected)^[223]
      • ASRAAM (expected)^[224]
      • Meteor (expected if Uttam AESA radar used in Mark 1A)^[225][226]
    • Air-to-surface missiles:
      • BrahMos-NG (expected)^[227]
      • DRDO Anti-Radiation Missile (expected)^[228]
    • Anti-ship missiles:^[220]
      • Brahmos-Ng (expected)^[229]
  • Bombs:
    
    • Laser-guided bombs^[230]
    • Glide bombs^[230]
    • Cluster weapons ^[220]
  • Other:
    
    • Drop tanks for ferry flight/extended range/loitering time
    • LITENING GR4 targeting pod^[222]

Avionics

• Hybrid version of Israel's Elta EL/M-2032 multi-mode fire control radar^[231]

• HAL Tejas timeline

Related lists

• List of fighter aircraft
• List of active Indian military aircraft

 

Wikimedia Commons has media related to HAL Tejas.

• Official Government of India Tejas site

Features and analysis:

• "Flying into the unknown" — A feature by The Hindu on the Tejas test pilots.
• "LCA and Economics" by Sunil Sainis and George Joseph
• "The Light Combat Aircraft Story", by Air Marshal MSD Wollen (Retd).
• The case to support the indigenous LCA programme, by Ashok Parthasarathi and Raman Puri.

Technical:

• An Approach to High AoA Testing of the LCA
• Development Flight Testing of the Tejas Light Combat Aircraft
• LCA Avionics And Weapon System Mission Computer Software Development: A Case Study

General:

• "Tejas / Light Combat Aircraft (LCA)", Fighter-planes.com
• "Dawn of Tejas" Aero India special report from flightglobal.com