EASA AD CF-2025-23
Nacelles/Pylons - Oil Cooler Fan Assembly Housing bracket cracking
Summary
The Canadian Airworthiness Directive CF-2025-23 addresses cracking in the oil cooler fan assembly housing bracket on Bell Textron Canada Limited (BTCL) Model 505 helicopters, specifically serial numbers 65011 to 65020 and 65022 to 65027. This directive mandates inspections and modifications to prevent potential failure of the mounting bracket. The issue involves the 'Z' shaped support bracket that may crack, posing a risk to the rear transmission system.
What Changed
CF-2025-23 introduces mandatory visual inspections of the right support bracket of the oil cooler fan assembly housing within 25 flight hours or 30 days of the directive's effective date. If cracks are found, immediate modification of the bracket is required before further flight. If no cracks are detected, the bracket must still be modified within 50 flight hours or 90 days to ensure continued airworthiness.
Why It Matters
This directive is critical for aviation professionals because a cracked mounting bracket can lead to interference with the transmission shaft and result in rear transmission failure, a dangerous condition. Operators and maintenance teams must comply promptly to avoid unsafe flight conditions and ensure regulatory compliance. The directive helps maintain helicopter safety and operational reliability.
What To Do
Operators of affected Bell 505 helicopters must perform a visual inspection of the right oil cooler fan assembly housing bracket within 25 flight hours or 30 days from May 7, 2025. If cracks are found, the bracket must be modified before the next flight. If no cracks are found, the modification must be completed within 50 flight hours or 90 days from the effective date. Compliance with Bell Textron's Alert Service Bulletin 505-23-35 or its approved revisions is required.