Airworthiness Directives; Airbus SAS Airplanes

The FAA is superseding Airworthiness Directive (AD) 2020-18- 04, which applied to Airbus SAS Model A350-941 and -1041 airplanes. AD 2020-18-04 required a one-time health check of the slat power control unit (PCU) torque sensing unit (TSU) for discrepancies, and corrective actions if necessary; a detailed inspection of the left-hand (LH) and right-hand (RH) slat transmission systems for discrepancies, and corrective actions if necessary; and LH and RH track 12 slat gear rotary actuator (SGRA) water drainage and vent plug cleaning (which includes an inspection for moisture). This AD was prompted by a determination that requiring modification of the PCU by replacing each affected slat PCU with a serviceable PCU (one having a different part number) is necessary. This AD continues to require the actions required by AD 2020-18-04, and also requires modification (replacement of each affected slat PCU with a slat PCU having a different part number), and revising the limitations on the installation of affected parts; as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.