Airworthiness Directives; Dassault Aviation Airplanes

The FAA is superseding Airworthiness Directive (AD) 2021-19- 20, which applied to all Dassault Aviation Model FALCON 7X airplanes. AD 2021-19-20 required amending the existing airplane flight manual (AFM) to incorporate a check and an operating limitation regarding the O<INF>2</INF> saver function. This AD was prompted by reports of defects that may prevent efficient deactivation of the O<INF>2</INF> saver function of crew oxygen masks and a determination that the AFM amendment required by AD 2021-19-20 may not be sufficient to mitigate the risk. This AD retains the requirements of AD 2021-19-20 and also requires physical deactivation of the O<INF>2</INF> saver function, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. This AD also limits the installation of affected parts under certain conditions. The FAA is issuing this AD to address the unsafe condition on these products.