AD 2020-11-13 Prompted By A Determination That It Is Necessary To Do A Replacement With New Nacelle Attachment Fittings

The FAA is superseding Airworthiness Directive (AD) 2010-23-04, which applied to all De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes.

AD 2010-23-04 required repetitive detailed inspections of the nacelle attachment fittings for cracks, a conductivity inspection of the nacelle attachment fittings, and replacement if necessary. This AD continues to require these inspections and replacement if necessary, removes a certain inspection requirement for certain airplanes, and adds a new requirement to replace the rear spar fitting and nacelle attaching structure with a new nacelle attachment fitting. This AD was prompted by a determination that it is necessary to do a replacement with new nacelle attachment fittings. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective July 14, 2020.

Supplementary Information: Transport Canada Civil Aviation (TCCA), which is the aviation authority for Canada, has issued Canadian AD CF-2010-30R2, dated July 30, 2019, (also referred to as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for all De Havilland Aircraft of Canada Limited (Type Certificate previously held by Bombardier, Inc.) Model DHC-8-400, -401, and -402 airplanes. You may examine the MCAI in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0099.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2010-23-04, Amendment 39-16493 (75 FR 68174, November 5, 2010) (“AD 2010-23-04”). AD 2010-23-04 applied to all De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. The NPRM published in the Federal Register on March 12, 2020 (85 FR 14423). The NPRM was prompted by reports of cracked nacelle attachment fittings, which a preliminary investigation determined to be caused by stress corrosion, and a determination that it is necessary to install new nacelle attachment fittings in order to address the unsafe condition. The NPRM proposed to continue to require repetitive detailed inspections of the nacelle attachment fittings for cracks, a conductivity inspection of the nacelle attachment fittings, and replacement if necessary. The NPRM also proposed to remove a certain inspection requirement for certain airplanes, and add a new requirement to replace the rear spar fitting and nacelle attaching structure with a new nacelle attachment fitting. The FAA is issuing this AD to address reports of cracked nacelle attachment fittings, which, if not detected and corrected, could compromise the structural integrity of the nacelle attachment fitting and possibly result in collapse of the landing gear. See the MCAI for additional background information.

FMI: www.regulations.gov