Summary
We propose to supersede Airworthiness Directive (AD) 2011-26- 03, which applies to certain The Boeing Company Model 777-200, -200LR, -300, and -300ER series airplanes. AD 2011-26-03 currently requires installing Teflon sleeving under the clamps of certain wire bundles routed along the fuel tank boundary structure, and cap sealing certain penetrating fasteners of the main and center fuel tanks. AD 2011-26-03 resulted from fuel system reviews conducted by the manufacturer. Since we issued AD 2011-26-03, we have received a report indicating that additional airplanes are affected by the identified unsafe condition. This proposed AD would add airplanes to the applicability. This AD would also add, for certain airplanes, detailed inspections of certain wire bundle clamps, certain Teflon sleeves, and certain fasteners; corrective actions if necessary; and installation of Teflon sleeves under certain wire bundle clamps. We are proposing this AD to prevent electrical arcing on the fueltank boundary structure or inside the fuel tanks, which could result in a fire or explosion.