AIRCRAFT FUEL SYSTEMS DESIGN STUDY
Final rept. Jul 1966-Jan 1967
GOODYEAR AEROSPACE CORP LITCHFIELD PARK AZ
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Data showed that the same weaknesses generally prevailed in all four of the fuel systems studied. The cast aluminum components in the systems are subject to gross fuel loss and flash ignition when located outside the fuel tanks, and they present an explosive hazard from ballistic impact when located inside the tanks. Fuel transfer components are inadequately compartmentalized or shrouded, leaving the system vulnerable to vapor explosion from fuel sprayed on ignition sources. Fuel tanks mounted too low in the airframe structure are susceptible to penetration from irregular ground objects. Access ports and filler necks mounted rigidly to the aircraft structure cannot break away from the structure in a crash environment the tanks tear away from these highly stressed fitting areas and severe fuel loss ensues. The fuel transfer outlets are mounted rigidly to the structure with no provisions for separation during a crash. Fuel-level indicator probes present a puncture hazard to fuel tanks. Fuel transfer lines generally consist of tubing that cannot withstand excessive deformations. Even flexible hose lacks the extensibility to withstand gross structural deformation. Since no self-sealing breakaway fittings are provided, either fittings or lines will fail. Rigid fuel line connections to bulkheads prevent line displacement and are another cause of fitting and line failures. Highly extensible fuel transfer lines, typified by the self-closing line, and properly located self-sealing breakaway fittings will reduce the problem of fitting failure by preventing load transfer to the fittings.