EASA AD CF-2025-59
Fuselage — Tailboom — Tailboom Attachment Hardware Fracture
Summary
The Canadian Airworthiness Directive CF-2025-59 addresses a critical safety issue involving Bell Textron Canada Limited model 407 helicopters. It mandates inspections and maintenance actions related to the tailboom attachment hardware, specifically focusing on the upper left longeron assembly and associated bolts to prevent tailboom separation during flight. This directive applies to all serial numbers of the Bell 407 helicopter.
What Changed
CF-2025-59 supersedes AD CF-2022-68 and introduces new requirements including repetitive inspections, torque checks, and replacement of tailboom attachment hardware. It also establishes a new airworthiness life limit for the tailboom attachment bolts and prohibits installation of certain affected parts. The directive incorporates Bell Alert Service Bulletin 407-24-134 and updates the Airworthiness Limitations Schedule.
Why It Matters
This directive is crucial for maintaining the structural integrity of the tailboom attachment on Bell 407 helicopters, directly impacting flight safety by preventing potential tailboom separation and loss of control. Operators, maintenance organizations, and compliance teams must adhere to these requirements to avoid serious accidents and ensure regulatory compliance. The inspections and hardware replacements help detect and mitigate fatigue or corrosion-related failures.
What To Do
Operators must comply with the directive by performing initial and repetitive detailed inspections and torque checks of the tailboom attachment hardware within specified intervals, starting within 50 hours air time or 30 days from the effective date. They must replace affected hardware as required and follow Bell ASB 407-24-134 instructions. Installation of certain upper left longeron assemblies is prohibited from the effective date. A detailed inspection must be completed within 600 hours air time or 12 months.