EASA AD CF-2025-33
Wing — Wing Access Panels with Un-trimmed Stiffeners and/or Reduced Thickness
Summary
Canadian Airworthiness Directive CF-2025-33 addresses wing access panels with un-trimmed stiffeners and/or reduced thickness on De Havilland Aircraft of Canada Limited model DHC-8 series aircraft, including models 102, 103, 106, 201, 202, 301, 311, 314, and 315. The directive focuses on ensuring the right-hand wing access panel stiffener is properly trimmed and that access panels of correct thickness are installed to prevent potential fuel tank ignition risks. It applies to all serial numbers of the affected models.
What Changed
This new Airworthiness Directive requires inspection and modification of both left-hand and right-hand outer wing access panels to verify trimming and correct thickness, as per De Havilland Service Bulletin 8-57-50. It prohibits installation of certain wing access panel part numbers (85710023, 8Z6267-001, IS8Q5700013-001) on DHC-8-300 series aircraft. The directive introduces a new wing access panel part number 85710008 that complies with the safety requirements.
Why It Matters
This directive is critical for aviation professionals because untrimmed stiffeners or incorrect panel thickness can cause contact with a fuel line coupling, creating a potential ignition source in the wing fuel tank during lightning strikes. Compliance ensures continued airworthiness and safety of the affected DHC-8 aircraft, reducing risk of fuel tank ignition. Operators, maintenance organizations, and compliance teams must address these issues to meet regulatory requirements and maintain safe operation.
What To Do
Operators of affected DHC-8 models must inspect and, if necessary, modify the wing access panels within 8000 flight hours or 48 months from July 16, 2025, whichever occurs first. They must follow the instructions in De Havilland Service Bulletin 8-57-50 or approved revisions. Additionally, installation of prohibited wing access panel part numbers on DHC-8-300 series aircraft is forbidden from the effective date of this directive.