Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 series airplanes, that currently requires inspections to detect damage of the support brackets and clamps of the transfer pipe of the tail tank, and of the transfer pipe assembly; and replacement of damaged parts, or installation of a doubler, if necessary. This action would add a requirement to install a fuel transfer pipe of the tail tank, and to install support brackets and clamps of the fuel feed pipe of engine No. 2, which constitutes terminating action for the repetitive inspections. This action would also require, for certain airplanes, removal of a temporary protective doubler installed on the fuel pipe assembly. This action is prompted by reports of cracking of the support brackets in the refuel and fuel transfer lines of the tail fuel tank and damage to the nylon clamps and transfer pipe assembly. The actions specified by the proposed AD are intended to prevent such cracking and damage, which could result in further damage to the transfer pipe assembly and possible fuel leakage.