EASA AD CF-2020-29R1
Flight Controls — Elevator Control System — Vertical Torque Tube Seizure — Sand Contamination of Bearing
Summary
The Airworthiness Directive CF-2020-29R1 titled "Flight Controls — Elevator Control System — Vertical Torque Tube Seizure — Sand Contamination of Bearing" applies to Bombardier Inc. BD-700-1A10 and BD-700-1A11 aircraft, serial numbers 9001 through 60081. It addresses contamination and corrosion of elevator torque tube bearings caused by sand, which can restrict free rotation and potentially lead to loss of pitch control. This directive mandates inspections and maintenance tasks to ensure continued safe operation of the elevator control system.
What Changed
This revision supersedes AD CF-2020-29 and integrates validated inspection intervals into new Certification Maintenance Requirement (CMR) tasks. It removes the previous reporting requirement and excludes aircraft delivered with the CMR tasks already incorporated. Additionally, it provides credit for inspections and functional tests performed before the effective date.
Why It Matters
This directive is critical for operators and maintenance organizations to prevent elevator control system failures caused by bearing contamination. Ensuring compliance reduces the risk of elevator torque tube seizure, which could compromise aircraft pitch control and safety. It also standardizes inspection intervals within approved maintenance manuals, aiding in regulatory compliance and operational reliability.
What To Do
Operators must amend their Transport Canada approved maintenance schedules within 30 days of the effective date to include the specified detailed inspection task for elevator torque tube bearings. Initial inspections are required within 3 months of the effective date or 63 months from the aircraft's entry into service, whichever is later. Repetitive inspections must then be performed at intervals specified in the applicable Time Limits/Maintenance Checks manuals.
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