Airworthiness Directives; Airbus SAS Airplanes

The FAA is adopting a new airworthiness directive (AD) for all Airbus SAS Model A350-941 and -1041 airplanes. This AD was prompted by a report of inadvertent auto flight system (AFS) altitude changes on the flight control unit (FCU). This AD requires revising the existing airplane flight manual (AFM) to include a procedure on the use of the AFS control panel ALT knob and replacing any affected FCU with a serviceable FCU, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. This AD also prohibits the installation of affected parts. The FAA is issuing this AD to address the unsafe condition on these products.