Action
Final rule; request for comments.
Summary
We are superseding an existing airworthiness directive (AD) for certain Model 777-200, -300, and -300ER series airplanes. That AD 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. This AD expands the applicability in the existing AD. This AD was prompted by fuel system reviews conducted by the manufacturer, which determined that electrical arcing on the fuel tank boundary structure or inside the fuel tanks could result in a fire or explosion. We are issuing this AD to correct the unsafe condition on these products.