Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes; and C-9 (military) airplanes. This proposal would require replacing the transformer ballast assembly in the first officer's console with a new, improved ballast assembly. This action is necessary to prevent overheating of the ballast transformers due to aging fluorescent tubes that cause a higher power demand on the ballast transformers, which could result in smoke in the cockpit. This action is intended to address the identified unsafe condition.