Wings - Wing to Fuselage Attachment Joints - Barrel Nut Cracking
- Published
- Effective
- Deadline
- Replaces
- 2011-24
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must perform initial torque checks and detailed inspections of barrel nuts within specified flight hour or calendar time limits based on aircraft usage. Repetitive inspections are required every 2000 flight hours or 12 months until the barrel nuts are replaced with the new Inconel 718 parts within 12,000 flight hours or 72 months from the AD's effective date. Installation of the old barrel nut part number DSC228-16 is prohibited after the AD's effective date.
Summary
Airworthiness Directive CF-2011-24R1 addresses the issue of barrel nut cracking in the wing to fuselage attachment joints on Bombardier Inc. DHC-8-400, -401, and -402 aeroplanes, serial numbers 4001 through 4437. This directive mandates inspections and replacement of barrel nuts to prevent structural integrity compromise caused by hydrogen embrittlement. It introduces a design change involving new Inconel 718 barrel nuts and related hardware to enhance durability.
What changed
This revision supersedes the original AD CF-2011-24 by mandating the replacement of existing barrel nuts with new Inconel 718 barrel nuts, which are more resistant to hydrogen embrittlement. It also introduces a torque verification procedure to address loose washers and establishes this replacement as a terminating action to repetitive inspections.
Why it matters
This directive is critical for maintaining the structural integrity of the wing to fuselage attachment joints, preventing potential failures that could compromise flight safety. Operators and maintenance organizations must ensure compliance to avoid unsafe conditions and regulatory penalties. The design change reduces the need for frequent inspections, improving maintenance efficiency and aircraft availability.
More for De Havilland Canada DHC-8
All 58- EASA AD CF-2026-47R1Wing – Wing Access Panels with Un-trimmed Stiffeners and/or Reduced Thickness - InspectionOct 13, 2026
- EASA AD CF-2026-47Wing – Wing Access Panels with Un-trimmed Stiffeners and/or Reduced ThicknessSep 28, 2026
- EASA AD CF-2026-38Maintenance Requirements Manual Part 2 - Airworthiness Limitation Items - AmendmentAug 17, 2026
- EASA AD CF-2026-37Time Limits / Maintenance Checks – Airworthiness Limitation Items – AmendmentAug 6, 2026
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