EASA AD 2026-0136
Flights Controls – Trimmable Horizontal Stabilizer Actuator Ballscrew Lower Splines – Inspection / Replacement
Summary
EASA Airworthiness Directive 2026-0136 is an airworthiness directive addressing corrosion issues in the trimmable horizontal stabilizer actuator (THSA) ballscrew lower splines on Airbus A318, A319, A320, and A321 aircraft. It applies to specific THSA part numbers that may suffer corrosion leading to potential loss of control of the airplane. The directive mandates inspections and possible replacement of affected parts to ensure continued airworthiness.
What Changed
This directive supersedes EASA AD 2012-0175R2 and updates the list of affected THSA part numbers by adding P/N 47145-347 and P/N 47145-367, which were newly identified as susceptible to corrosion. It retains the previous inspection and corrective action requirements while clarifying terminating actions and installation restrictions for affected parts.
Why It Matters
This AD is critical for aviation professionals because corrosion in the THSA ballscrew lower splines can lead to actuator failure and loss of airplane control. Operators, maintenance organizations, and compliance teams must monitor and inspect affected parts to prevent unsafe conditions and ensure regulatory compliance. Failure to comply could result in unsafe flight conditions and regulatory penalties.
What To Do
Operators must perform detailed repetitive inspections of the affected THSA ballscrew lower splines within specified timeframes, starting before the THSA reaches 22 years in service or within three months after 21 September 2012, whichever is later, and then every 24 months. If corrosion is found, corrective actions including additional inspections and replacement must be carried out as per the Airbus Service Bulletin. Installation of affected THSAs is restricted unless they meet specific serviceability criteria and inspections.
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