Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9-31 and DC-9-32 airplanes. This proposal would require replacement of certain power relays, and subsequent repetitive cleaning, inspecting, repairing, and testing of certain replaced power relays. This action is necessary to prevent internal arcing of the left and right generator power relays, auxiliary power relays, and external power relays, and consequent smoke and/or fire in the cockpit and cabin. This action is intended to address the identified unsafe condition.