EASA AD CF-2023-23
Flight Controls — Replacement of Horizontal Stabilizer Trim Actuator Upper Gimbal Bushing Flanges
Summary
Canadian Airworthiness Directive CF-2023-23 mandates the replacement of the horizontal stabilizer trim actuator (HSTA) upper gimbal bushing flanges on Airbus Canada Limited Partnership aircraft models BD-500-1A10 and BD-500-1A11. This directive applies to specific serial numbers of these models and aims to address a potential flight control issue. The directive ensures continued airworthiness and safety of the affected aircraft.
What Changed
CF-2023-23 introduces a mandatory replacement of the HSTA upper gimbal bushing flanges with redesigned flanges that have material removed to prevent fouling and interference. Previously, this replacement was managed as a fleet campaign without an airworthiness directive, but this AD formalizes the requirement due to incomplete compliance within the planned timeframe.
Why It Matters
This directive is critical for operators and maintenance organizations because fouling between the gimbal bushing and the HSTA structural fitting can prevent engagement of the secondary load path, risking loss of pitch control if the primary load path fails. Compliance ensures the aircraft's flight control system remains reliable and safe, avoiding potential in-flight control issues.
What To Do
Operators must replace the HSTA upper gimbal bushing flanges according to Airbus Canada Limited Partnership Service Bulletin BD500-274002, Issue 002 or later approved revisions. This replacement must be completed before accumulating 9,350 flight hours from the AD's effective date of April 19, 2023. Credit is given for prior replacements done per earlier service bulletin versions.
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