Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This proposal would require performing a one-time inspection for chafing of certain electrical wire bundles behind the flight engineer's panel in the cockpit; repairing any chafed wire bundles, if necessary; and installing Teflon sleeving over the inspected wire bundles and rerouting them. This action is necessary to prevent burning of electrical wires, which could result in smoke in the cockpit and loss of function of several airplane systems. This action is intended to address the identified unsafe condition.