EASA AD 2021-0033
Flight Controls — Trimmable Horizontal Stabilizer Actuator Lower Attachment Parts — Inspection
Summary
EASA Airworthiness Directive 2021-0033 is an airworthiness directive addressing the inspection of trimmable horizontal stabilizer actuator (THSA) lower attachment parts on Airbus A330 and A340 aeroplanes. It applies to various Airbus A330 and A340 models across all manufacturer serial numbers. The directive mandates a detailed inspection to verify correct installation of the THSA lower attachment parts to ensure flight control safety.
What Changed
EASA Airworthiness Directive 2021-0033 introduces a one-time detailed inspection requirement for the THSA lower attachment parts due to reported incorrect installations caused by human error during production and maintenance. It also prohibits the use of certain Airbus Aircraft Maintenance Manual tasks that do not contain the corrected instructions and requires corrective actions if discrepancies are found during inspection.
Why It Matters
This directive is critical for aviation professionals because incorrect installation of THSA lower attachment parts can lead to loss of the primary load path and activation of a secondary load path that is only designed for limited use, potentially reducing aircraft control. Operators and maintenance organizations must ensure compliance to maintain aircraft safety and airworthiness. The directive also impacts maintenance procedures by restricting the use of outdated manual tasks until corrected instructions are incorporated.
What To Do
Operators of affected Airbus A330 and A340 aeroplanes must perform a detailed inspection of the THSA lower attachment parts within 1,000 flight hours from 8 February 2021, the effective date of the directive. If any installation discrepancies are found, corrective actions must be completed before the next flight. Additionally, from the effective date, the use of certain Airbus AMM tasks is prohibited unless they contain the updated instructions from the Airbus Alert Operators Transmission A27L014-20.
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