AD FAA-2013-0306

We are adopting a new airworthiness directive (AD) for all Dassault Aviation Model FALCON 7X airplanes. This AD requires revising the aircraft flight manual (AFM); performing operational tests of the oxygen mask oxygen assembly; and replacing affected stowage boxes, which terminates the AFM revision and operational tests. This AD was prompted by failure of the flight crew oxygen supply due to a potentially defective flight crew mask oxygen assembly. We are issuing this AD to prevent failure to supply oxygen upon demand to the flight crew in flight in "100%" and "Emergency" modes, which, in an emergency, may result in incapacitation of the flight crew.