Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 777-200 and -300 series airplanes. This proposed AD would require inspecting the valve control and indication wire bundles of the fuel system of the wing rear spar for discrepancies, and corrective action if necessary. This proposed AD is prompted by reports of six incidents of the wire bundles chafing against the rear spar stiffeners outside the fuel tank. We are proposing this AD to prevent this chafing, which could result in wire damage leading to a short circuit, subsequent ignition of flammable vapors, and possible uncontrollable fire during fueling or flight.