EASA AD CF-2021-34
Fuselage — Tailboom — Lower Skin Cracking
Summary
Canadian Airworthiness Directive CF-2021-34 addresses a structural issue involving lower skin cracking on the tailboom of Bell Textron Canada Limited model 407 helicopters, specifically serial numbers 53000 through 53900, 53911 through 54166, 54300 and subsequent. The directive mandates inspections and maintenance actions to detect and correct fatigue cracks near the horizontal stabilizer cutout to ensure continued airworthiness. This AD is issued under Canadian Aviation Regulation 521.427 and applies to affected Bell 407 helicopters.
What Changed
CF-2021-34 introduces a new inspection zone below the left-hand side horizontal stabilizer cutout on the tailboom assembly of Bell 407 helicopters. It mandates compliance with the revised Chapter 4 Airworthiness Limitations Schedule in the Bell 407 Maintenance Planning Information manual, requiring inspections and corrective actions for tailboom lower skin cracking. This is a new regulation addressing a recently identified fatigue cracking issue.
Why It Matters
This directive is critical for maintaining the structural integrity of the tailboom on Bell 407 helicopters, preventing potential failure due to fatigue cracking. Operators and maintenance organizations must incorporate the new inspection requirements to avoid unsafe conditions that could compromise flight safety. Compliance ensures continued airworthiness and regulatory adherence under Canadian aviation standards.
What To Do
Operators must perform inspections and maintenance tasks as specified in Bell 407 MPI Chapter 4, ALS Issue 3 or later approved revisions, starting at the next scheduled tailboom assembly inspection after 5 November 2021. Any detected defects must be corrected within the compliance times specified or before further flight if no time is given. Components must be replaced before exceeding their airworthiness life limits.
AI-generated summary from official EASA source document. Always verify against the original.