Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to certain Boeing Model 747-100, -200, and - 300 series airplanes, that would have required the replacement of certain switches located behind the cabin attendant's panel at door 4 right, with new improved switches. That proposal was prompted by reports indicating that fires have occurred on some airplanes due to the internal failure of some of these switches. This action revises the proposed rule by adding a requirement to replace switches located at door 2 right. The actions specified by this proposed AD are intended to prevent the installation and use of switches that could short circuit when they fail, and consequently cause fire and smoke aboard the airplane.