Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 series airplanes. This proposal would require a one-time inspection of the separation between the galley power feeder and static ground wiring, and the adjacent passenger oxygen system tubing in the forward ceiling area above the door 4 galley; and rerouting of wiring, and installing clamps and sleeves, if necessary. This proposal is prompted by reports of inadequate clearance between the galley power feeder wiring and passenger oxygen system tubing. The actions specified by the proposed AD are intended to prevent such inadequate clearance, which could result in a fire in the ceiling area above the door 4 galley due to chafing of wiring on oxygen system tubing.