A significant percentage of general aviation aircraft accidents result in postcrash fires due to the ignition of spilled fuel. This condition often causes further injury or even death to the occupants.Testing was undertaken to examine the performance of light-weight, flexible, crash-resistant fuel cells with frangible fuel line couplings. Included in the experiments were four full-scale crash tests of a typical light twin-engined aircraft. In three of these tests, the crash-resistant fuel system performed satisfactorily. However, the fourth test, which used the lightest weight tanks, resulted in tank failures which indicated a possible lower strength limit to the tank material.