Airworthiness Directives; Airbus Airplanes

We are adopting a new airworthiness directive (AD) for all Airbus Model A330-200, -200 Freighter, and -300 series airplanes, and all Airbus Model A340-200, -300, -500, and -600 series airplanes. This AD was prompted by reports of premature aging of certain chemical oxygen generators in the passenger compartment that resulted in failure of the generators to activate. This AD requires inspecting to determine if certain passenger chemical oxygen generators are installed, and replacement of affected generators. We are issuing this AD to prevent failure of the chemical oxygen generator to activate during an emergency situation, which could result in unavailability of oxygen and possible incapacitation of the occupants.