EASA AD CF-2020-39
Nacelles/Pylons — Main Landing Gear Side Brace Fitting to A-frame Joint — Fastener Holes Not Cold-worked
Summary
Canadian Airworthiness Directive CF-2020-39 addresses an issue with the nacelles/pylons on De Havilland Aircraft of Canada Limited DHC-8-400, -401, and -402 aeroplanes, specifically serial numbers 4081 through 4591. The directive focuses on the main landing gear side brace fitting to the A-frame joint where fastener holes were not cold-worked as required. This condition poses a risk of cracking and potential main landing gear collapse.
What Changed
CF-2020-39 introduces a mandatory corrective action requiring the removal of fasteners on the nacelle A-frame side brace sub-assemblies, cold-working of the holes, and installation of oversize fasteners. This is to ensure compliance with engineering specifications and prevent structural failure. The directive applies to affected aircraft within specified serial numbers and flight cycle limits.
Why It Matters
This directive is critical for aviation professionals because failure to address the non-cold-worked fastener holes can lead to cracking of the A-frame bottom flange and possible main landing gear collapse. Operators and maintenance organizations must comply to maintain aircraft airworthiness and safety. Compliance ensures continued operational safety and regulatory adherence under Canadian Aviation Regulations.
What To Do
Operators of affected De Havilland DHC-8-400 series aircraft must remove the existing fasteners on the nacelle A-frame side brace sub-assemblies, cold-work the holes, and install oversize fasteners following the instructions in Service Bulletin 84-54-32. These actions must be completed within 48 months or 8,000 flight hours from October 28, 2020, or before reaching 40,000 total flight cycles, whichever occurs first.
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