Hyperspectral remote sensing needs to address the complex spectral variability factors associated with it, and their effects on the accuracy of information derived. This issue was examined in a preliminary manner by analyzing apparent reflectance spectral signature repeatability of common test target panels in two image data collects of the HYperspectral Digital Imagery Collection Experiment (HYDICE) airborne sensor. The results obtained demonstrate where more spectral variability research is needed to further investigate this issue, and the phenomenology behind it.