Airworthiness Directives; McDonnell Douglas Corporation Model MD-11 and MD-11F Airplanes
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Model MD-11 and MD-11F airplanes. That AD currently requires a one-time inspection to determine if metallic transitions are installed on wire harnesses of the tail tank fuel transfer pumps, and to determine if damaged wires are present; and repair, if necessary. That AD also requires repetitive inspections of the repaired area; and a permanent modification of the wire harnesses if metallic transitions are not installed, which would terminate the repetitive inspections. This new AD requires modifying the case grounding for the alternate fuel pump of the tail tank, the leak detection thermal switch grounding for the number 2 engine, and wire braid grounding in the empennage and number 2 engine inlet. This AD also removes one airplane from the applicability of the existing AD. This AD results from reports that the wire assembly for the alternate fuel pump is missing a case ground wire, and the lightning protection wire braid for wire assemblies located in the empennage and number 2 engine inlet are grounded improperly. We are issuing this AD to prevent insufficient grounding of the fuel pump, which in combination with an electrical failure within the fuel pump and a compromised electrical bond could cause a fuel tank ignition, resulting in consequent fire or explosion.
McDonnell Douglas Corporation Model MD-11 and MD-11F