The United States Federal Aviation Administration ( FAA ) has issued a new airworthiness directive (AD) for the Boeing 777, following an analysis that similar failures, which were apparent on Boeing 747 aircraft, could also occur on Triple Sevens. Issues related to fuel tanks The FAA stated that the electrical bonding of the engine fuel feed tube penetrating the fuel tanks of 777 aircraft, including the 777-200, 777-200LR, 777-300ER, and 777F, which are all powered by the General Electric (GE) GE90 engine, was the main design feature that prevented an ignition source from appearing inside the fuel tank in the event of lightning striking the engine nacelle. “The fuel feed lightning protection features include the spar bulkhead fitting that redirects the majority of current during a lightning event.
” According to the regulator, separate bonding jumpers outside and inside the fuel tank provide additional electrical paths for current from lightning strikes, with an additional non-bonding feature and an encapsulation seal over the spar fitting inside the fuel tank, providing further protection from sparking. The issue was first discovered on all 747 aircraft, and to address it, the FAA issued a final rule directive in November 2023. However, analysis from reports related to the AD for the 747s has allowed Boeing and the FAA to determine that 777s are likely to experience similar encapsulation and bonding failures.
“On Model 747 airplanes, the bonding jumper outside the fuel .
