EASA AD CF-2023-26
Flight Controls — Pitch Trim — Mis-Trimmed Horizontal Stabilizer Leading to Controllability Issues
Summary
Canadian Airworthiness Directive CF-2023-26 addresses a flight control issue involving the pitch trim system on Bombardier BD-100-1A10 Challenger 300 and 350 aircraft, serial numbers 20003 through 20910. The directive highlights problems caused by a mis-trimmed horizontal stabilizer leading to controllability difficulties, especially after autopilot disconnect. It mandates updates to the Airplane Flight Manual to improve pilot procedures during such events.
What Changed
This new Airworthiness Directive requires revising the Airplane Flight Manual for the affected Bombardier Challenger 300 and 350 models to include a caution in the Auto Flight Non-Normal Procedures. The update instructs flight crews to minimize airspeed and configuration changes when disconnecting the autopilot in an out-of-trim condition. It also mandates informing all flight crews about these procedural changes.
Why It Matters
This directive is critical for aviation professionals because it addresses a safety risk where improper horizontal stabilizer trim can cause unexpected pitch upsets and high control forces after autopilot disengagement. Operators and maintenance teams must ensure compliance to prevent potential loss of aircraft controllability. Flight crews need to be aware of the updated procedures to safely manage autopilot disconnect scenarios and maintain safe flight handling.
What To Do
Operators of Bombardier BD-100-1A10 Challenger 300 and 350 aircraft must amend their Airplane Flight Manuals as specified by Transport Canada within 60 days of the directive's effective date. They must also brief all flight crews on the new procedures and ensure adherence to the updated guidance during flight operations.
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