EASA AD CF-2018-18
Tail Rotor Drive — Loose Tail Rotor Gearbox
Summary
Canadian Airworthiness Directive CF-2018-18 is an emergency directive addressing a safety issue on Bell Helicopter Textron Canada Limited model 429 helicopters, specifically serial numbers 57001 through 57321, 57323 through 57341, 57343 through 57346, 57348, and 57350. The directive focuses on inspecting and securing the tail rotor gearbox to prevent looseness that could lead to structural damage and loss of helicopter control. It mandates inspections and torque checks following BHTCL Alert Service Bulletin 429-18-40.
What Changed
This new emergency airworthiness directive introduces mandatory inspections and torque checks of the tail rotor gearbox retaining hardware on affected Bell 429 helicopters. It requires immediate action before the next flight and within 5 hours air time or 7 days to detect and correct any looseness in the gearbox assembly. The directive also allows the use of later approved revisions of the referenced service bulletin for compliance.
Why It Matters
This directive is critical for aviation professionals because a loose tail rotor gearbox can cause structural damage and potentially lead to loss of helicopter control, posing serious safety risks. Operators, maintenance organizations, and compliance teams must ensure timely inspections and corrective actions to maintain airworthiness and regulatory compliance. Failure to comply could result in grounding of affected aircraft and increased safety hazards.
What To Do
Operators of Bell 429 helicopters within the specified serial number range must inspect the tail rotor gearbox for looseness before the next flight after 16 July 2018, following Part I of BHTCL Alert Service Bulletin 429-18-40. Additionally, within 5 hours air time or 7 days from the effective date, a torque check of the retaining hardware must be performed per Part II of the service bulletin. If any looseness or movement is detected, operators must contact BHTCL Product Support Engineering for approved corrective actions before further flight.
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