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Results of investigation to develop a technological basis for overcoming aircraft lightning-strike hazards associated with turbojet aircraft fuel vents are discussed. Flame propagation and arrester experiments were performed with high-voltage and high-current facilities and repeated in a combustion research facility using a drive tube to simulate impulse effects of natural lightning. Flame propagation through actual aircraft vent systems containing flammable fuel-air mixtures was demonstrated, and characteristic flame propagation properties were measured and duplicated in laboratory apparatus. Preliminary assessment of problems involved in designing effective flame arresters and explosion suppression systems was made. Lightning-stroke patterns in fuel vent region were analyzed as to inferable hazard significance.

The trend toward much greater use of general aviation aircraft under all weather conditions for instrument flight almost certainly suggests a greater amount of lightning damage and possible hazard from lightning discharges. Many years of experience in observing lightning problems on commercial transport aircraft (one lightning damage report per year per aircraft) indicates the areas of possibly serious problems. The techniques obtained from lightning protection development programs on nearly all commercial aircraft are often directly applicable to general aviation aircraft but require careful, intelligent application and, most important, an awareness, particularly by structure and fuel systems designers of the possible problems.