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 relocating the B7- 28 bus located in the upper main circuit breaker in the rear cockpit observer's station from the lower to the upper terminals of the circuit breakers in Row P. This action is necessary to prevent insufficient clearance and contact between the B7- 28 bus and an adjacent panel, which could result in arcing damage, smoke, and/or fire in the upper main circuit breaker panel. This action is intended to address the identified unsafe condition.