Action
Final rule.
Summary
We are superseding Airworthiness Directive (AD) 2009-26-16 for certain The Boeing Company Model MD-11 and MD-11F airplanes. AD 2009- 26-16 required inspecting to determine if wires touch the upper surface of the center upper auxiliary fuel tank, and marking the location, as necessary; inspecting all wire bundles above the center upper auxiliary fuel tank for splices and damage; inspecting for damage to the fuel vapor barrier seal and upper surface of the center upper auxiliary fuel tank; and performing corrective actions, as necessary. AD 2009-26-16 also required installing nonmetallic barrier/shield sleeving, new clamps, new attaching hardware, and a new extruded channel. This new AD requires inspections of additional center upper auxiliary fuel tank locations and corrective actions as necessary. This AD was prompted by reports that identified additional locations where inspections and corrective actions of the center upper auxiliary fuel tank are needed. We are issuing this AD to reduce the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.