Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes. This proposal would require electrical resistance measurements of the ground studs of the No. 2 generator in the electrical power center of the center accessory compartment for proper electrical bonding and of the ground studs and circuit breaker terminations in the forward cargo compartment to detect looseness and for proper electrical bonding; and corrective actions, if necessary. This proposal is prompted by an incident of charred insulation blankets in the forward cargo compartment in the area of the external ground power receptacle and the galley external power circuit breakers, and another incident of a No. 2 "generator off" alert while the generator was still on line. The actions specified by the proposed AD are intended to prevent arcing and overheating of terminals and consequent smoke and fire in the forward cargo compartment due to improper bonding of ground studs in the forward cargo compartment and in the electrical power center and due to improper installation of circuit breaker terminations.