EASA AD CF-2022-33
Tail Rotor Drive — Failure of Tail Rotor Drive Shaft with Bonded Adapters
Summary
The Canadian Airworthiness Directive CF-2022-33 addresses the failure risk of tail rotor drive shafts with bonded adapters on Bell Textron Canada Limited model 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters. It mandates inspections and proof load tests to detect adhesive bond degradation in segmented tail rotor drive shaft assemblies. This directive aims to prevent loss of tail rotor drive and potential loss of helicopter control.
What Changed
CF-2022-33 introduces mandatory compliance with Bell Alert Service Bulletins 206-20-139 and 206L-20-184 for repetitive detailed inspections and proof load testing of affected tail rotor drive shafts. It requires operators to identify whether their helicopters have bonded tail rotor drive shafts and to perform corrective actions accordingly. The directive focuses on the assemblies themselves rather than the helicopters as a whole.
Why It Matters
This directive is critical for aviation professionals to ensure the structural integrity of tail rotor drive shafts, which are vital for helicopter control. Operators and maintenance organizations must implement the inspections and tests to detect adhesive bond failures that are not easily identified by standard inspections. Compliance reduces the risk of in-flight tail rotor drive loss, enhancing flight safety and regulatory adherence.
What To Do
Operators must determine if their helicopters have affected bonded tail rotor drive shafts within 75 hours air time or 3 months from 2022-06-29. For helicopters with affected parts, detailed inspections and proof load tests must be performed before further flight and repeated every 300 hours air time or 12 months. Damaged or failed parts must be replaced with serviceable riveted assemblies before flight. Only serviceable parts are eligible for installation from the effective date.
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