EASA AD CF-2019-15
Tail Rotor System — Incorrect Assembly
Summary
Canadian Airworthiness Directive CF-2019-15 is an emergency directive addressing an incorrect assembly issue in the tail rotor system of Bell Helicopter Textron Canada Limited model 429 helicopters, serial numbers 57001 through 57363. The directive focuses on the improper installation of the Curvic Coupling Part Number 429-012-120-101, which can lead to loosening of the tail rotor assembly and loss of drive to the outboard tail rotor blades. This condition affects the helicopter's directional control and safety.
What Changed
This new Airworthiness Directive introduces mandatory inspections and corrective actions for the tail rotor assembly on affected Bell 429 helicopters. It requires inspections within 10 hours air time or 7 days from the effective date and mandates immediate correction of any defective conditions found. Additionally, it requires reporting of any anomalies within 3 days after inspection completion.
Why It Matters
This directive is critical for aviation professionals because improper assembly of the tail rotor system can cause severe vibration and loss of directional control, posing a significant safety risk. Operators, maintenance organizations, and compliance teams must ensure timely inspections and repairs to maintain airworthiness and regulatory compliance. Failure to comply could result in unsafe flight conditions and regulatory penalties.
What To Do
Operators of Bell 429 helicopters with serial numbers 57001 through 57363 must inspect the tail rotor assembly within 10 hours air time or 7 days from April 27, 2019, following Bell Helicopter Textron Canada Limited Alert Service Bulletin 429-19-45 dated April 16, 2019. Any defects found must be corrected before further flight, and any anomalies must be reported within 3 days after inspection completion. Use of later approved revisions of the service bulletin is permitted.
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