Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 757-200, -200CB, and -300 series airplanes. This proposal would require determining the part numbers of the master control valve on the pressure bottles that activate the off-wing escape slides, and corrective action, if necessary. This action is necessary to prevent failure of an escape slide to deploy or inflate correctly, which could cause the slide to be unusable during an emergency evacuation and result in consequent injury to passengers or crewmembers. This action is intended to address the identified unsafe condition.