Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 and MD-11F series airplanes, that currently requires, among other things, repetitive visual inspections to detect discrepancies of the fuel pipe of the fuel transfer system of the tail tank and associated mounting bracket located in the aft fuselage compartment. That AD was prompted by reports of cracking or bending of the fuel pipe mounting support and/or attaching bracket in the aft fuselage compartment due to a fuel pressure surge that caused repetitive loading of this area. This action would add a requirement to install a restraint on the tail tank fuel pipe, which would terminate the repetitive visual inspections. The actions specified by the proposed AD are intended to prevent such cracking/bending, which could expose the fuel pipe coupling O-ring. An exposed O-ring could lose its sealing effect and could allow a fuel leak in the aft fuselage compartment, which would present a fire hazard.