Airworthiness Directives; Airbus Airplanes

We are adopting a new airworthiness directive (AD) for all Airbus Model A318, A319, A320, and A321 series airplanes. This AD was prompted by reports of premature aging of certain passenger chemical oxygen generators that resulted in the generators failing to activate. This AD requires an inspection to determine if certain passenger chemical oxygen generators are installed and replacement of affected passenger chemical oxygen generators. We are issuing this AD to prevent failure of the passenger chemical oxygen generator to activate and consequently not deliver oxygen during an emergency, possibly resulting in injury to the airplane occupants.