Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-300, -400, and -500 series airplanes; and Model 757-200 and -200CB series airplanes. This proposal would require inspection of the applicable body station frames for open body station frames and related investigative/corrective actions; and installation of lanyard hook brackets and lanyard assemblies under the air conditioning overhead ducts, as applicable. This action is necessary to prevent loosened or disconnected overhead ducts from causing ceiling panels to drop below the minimum height of the evacuation zone for the passenger cabin, which could result in inadequate height for safe exit in the event of an emergency evacuation. This action is intended to address the identified unsafe condition.