Flight Controls — Horizontal Stabilizer — Unintended Horizontal Stabilizer Motion
- Published
- Effective
- Deadline
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of affected Bombardier BD-100-1A10 aircraft must modify the trim switch wiring within 3000 flight hours or 5 years from the effective date of December 21, 2023, whichever occurs first. After modification, the aileron and horizontal stabilizer trim systems must be tested according to the applicable Bombardier Service Bulletin instructions. Compliance with these actions is mandatory to continue legal flight operations.
Summary
Canadian Airworthiness Directive CF-2023-77 addresses unintended horizontal stabilizer motion on Bombardier BD-100-1A10 aircraft, serial numbers 20003 through 20936. This directive mandates modifications to the horizontal stabilizer pitch trim switch wiring to prevent uncommanded or opposite-direction stabilizer movements. The AD aims to enhance flight safety by correcting wiring issues that could compromise aircraft controllability.
What changed
CF-2023-77 introduces a requirement to modify the electrical circuitry connecting the trim switches to the aileron trim actuator and the Horizontal Stabilizer Electronic Control Unit. This modification segregates pilot and co-pilot trim enable signals to prevent unintended horizontal stabilizer motion. The directive also requires testing of the trim systems after the wiring changes are completed.
Why it matters
This directive is critical for operators and maintenance organizations because unintended horizontal stabilizer motion can lead to loss of aircraft control and increased pilot workload. Compliance ensures safer flight operations by addressing a root cause of previous in-service incidents involving stabilizer trim faults. It also helps maintain regulatory compliance and reduces the risk of accidents related to flight control anomalies.
More for Bombardier BD-100
All 41- EASA AD CF-2025-58Time Limits/Maintenance Checks (TLMC) — Airworthiness Limitations (AWL)Nov 14, 2025
- EASA AD CF-2025-42Flight Controls — Horizontal Stabilizer — Autopilot Inability to Trim Horizontal StabilizerAug 28, 2025
- EASA SIB CASA-2025-03Flight Controls — Unannunciated Loss of Ground Lift Dump Spoilers due to Faulty Throttle Quadrant AssemblyApr 9, 2025
- EASA AD CF-2024-38Flight Controls — Horizontal Stabilizer Trim Actuator (HSTA) — Incomplete OverhaulNov 15, 2024
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