Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 737-300, -400, -500, -600, -700, -800 and -900 series airplanes; and Model 757-200 and -300 series airplanes. This proposed AD would require modifying the activation mechanism in the chemical oxygen generator of each passenger service unit (PSU). This proposed AD results from several reports indicating that some chemical oxygen generators failed to activate during in-flight decompression events. These failures were due to fracture of components between the passenger oxygen mask and the release pin in the oxygen generator. We are proposing this AD to prevent failure of the activation mechanism of the chemical oxygen generator, which could result in the unavailability of supplemental oxygen and possible incapacitation of passengers and cabin crew during an in-flight decompression.