AD 2021-12-02 Prompted By A Report That A Number Of Nacelle A-Frames Were Not Manufactured In Accordance With Engineering Drawings

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes.

This AD was prompted by a report that a number of nacelle A-frames were not manufactured in accordance with engineering drawings. This AD requires, depending on airplane configuration, removing the fasteners on the nacelle A-frame side brace sub-assemblies, doing an eddy current inspection for cracking, cold-working the holes, installing oversize fasteners, re-identifying the reworked side brace fitting and A-frame, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective July 20, 2021.

Supplementary Information: Transport Canada Civil Aviation (TCCA), which is the aviation authority for Canada, has issued TCCA AD CF-2020-39, dated October 14, 2020 (TCCA AD CF-2020-39) (also referred to as the Mandatory Continuing Airworthiness Information, or the MCAI), to correct an unsafe condition for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series 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-2021-0183.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. The NPRM published in the Federal Register on March 22, 2021 (86 FR 15149). The NPRM was prompted by a report that a number of nacelle A-frames were not manufactured in accordance with engineering drawings. The holes in the side brace sub-assemblies were not cold-worked as required. As a result the side brace fitting might not meet its fatigue life, and cracking of the A-frame bottom flange may result. The NPRM proposed to require, depending on airplane configuration, removing the fasteners on the nacelle A-frame side brace sub-assemblies, doing an eddy current inspection for cracking, cold-working the holes, installing oversize fasteners, re-identifying the reworked side brace fitting and A-frame, and repair if necessary. The FAA is issuing this AD to address possible cracking of the A-frame. This condition, if not addressed, may lead to collapse of the main landing gear (MLG). See the MCAI for additional background information.

FMI: www.regulations.gov