Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all McDonnell Douglas Model MD-11 and MD-11F airplanes. This proposed AD would require installing bracket assemblies and jumper wires in the center main wheel well to improve the bonding path between the structure (wall) of the lower auxiliary fuel tank and its internal fuel pumps; measuring the electrical resistance between the fuel pump housings and the fuel tank structure; and doing corrective actions if necessary. This proposed AD results from fuel system reviews conducted by the manufacturer. We are proposing this AD to detect and correct an inadequate bond between the internal fuel pump housings and the structure of the lower auxiliary fuel tank. This condition, if not corrected, could fail to meet fault current requirements and result in a potential ignition source that, in combination with flammable fuel vapors, could cause a fuel tank explosion and consequent loss of the airplane.