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 replacement of the air driven generator (ADG) wire assembly with a new, increased length wire assembly. This action would require, among other actions, replacement of the existing ADG wire assembly in the right air conditioning compartment with a certain new wire assembly. This action also would expand the applicability of the existing AD to include additional airplanes. This proposal is prompted by an investigation that revealed the length of the new wire assembly is too long and causes the assembly to chafe against the left emergency alternating current bus of the ADG. The actions specified by the proposed AD are intended to prevent loss of the charging capability of the airplane battery due to chafing. Loss of the charging capability of the airplane battery, coupled with a loss of all normal electrical power, could prevent continued safe flight and landing of the airplane.