Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737, 757, 767, and 777 series airplanes. This proposal would require a one-time general visual inspection to determine the vendor and manufacturing date of all oxygen masks in the passenger cabin; and corrective action, if necessary. This proposal is prompted by a report that passengers were unable to activate supplemental oxygen generators during an in- flight decompression due to stress corrosion cracking of the crimped copper alloy ferrules used to secure loops on the lanyard ends. The actions specified by the proposed AD are intended to prevent failure of the supplemental oxygen system to deliver oxygen to the passengers and flight attendants in the event of decompression, which could result in injury to passengers and flight attendants.