Airworthiness Directives; Boeing Model 777 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 777 series airplanes. This action requires a one-time measurement of the electrical bonding resistance between the wing spar connectors of the fuel quantity indicating system (FQIS) and the spar structure, installation of bonding jumpers, a one- time operational check of the FQIS system, and corrective action, if necessary. This action is necessary to ensure adequate electrical bonding between the wing spar connectors of the FQIS and the spar structure. Inadequate electrical bonding, in the event of a lightning strike, could cause electrical arcing and ignition of fuel vapor in the main or center fuel tank, which could result in a fuel tank explosion. This action is intended to address the identified unsafe condition.