EASA AD 2021-0275
Flight Controls — Slat Transmission Shafts / Slat Power Control Unit Torque Sensing Units — Inspection / Modification
Summary
EASA Airworthiness Directive 2021-0275 is an airworthiness directive addressing Airbus A350-941 and A350-1041 aeroplanes. It focuses on inspection and modification requirements for slat transmission shafts and slat power control unit torque sensing units, specifically targeting affected slat PCUs with part numbers 4785A0000-04 and 4785A0000-05. The directive aims to ensure continued safe operation by mandating inspections, health checks, and eventual replacement of affected parts.
What Changed
EASA AD 2021-0275 supersedes the previous AD 2021-0053R1 and introduces the requirement to replace affected slat power control units with a new serviceable part (P/N 4785A0000-06) within 18 months. It retains repetitive health checks for torque sensing units until the replacement is completed and removes the previous requirement for water drainage and vent plug cleaning of the slat gear rotary actuators. The AD also allows installation of affected parts under strict conditions until replacement.
Why It Matters
This directive is critical for aviation professionals as it addresses a safety issue involving potential slat system jams caused by wear in torque sensing units, which could lead to slat surface disconnection and reduced aircraft control. Operators and maintenance organizations must comply to prevent unsafe conditions during flight, particularly during landing phases. Compliance ensures continued airworthiness and regulatory conformity, reducing risk of incidents related to slat system failures.
What To Do
Operators of Airbus A350-941 and A350-1041 aeroplanes must perform detailed inspections and health checks of the left-hand and right-hand slat transmission systems and torque sensing units within specified flight cycle or time thresholds. Any discrepancies found require contacting Airbus for corrective instructions. Affected parts must be replaced with serviceable parts within 18 months of the AD's effective date, which will terminate the need for repetitive health checks. Installation of affected parts is restricted and must be accompanied by health checks until replacement.
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