Airworthiness Directive · Amendment 39-22770 · Fuselage
De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
This AD applies to De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Model DHC-8-401 and -402 airplanes, certificated in any category, having serial numbers 4001 and 4003 through 4624 inclusive.
The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports of moisture in the wing- to-fuselage joint, between the mating front spar and rear spar frame segments. This AD requires a visual inspection of the fuselage front and rear spar frames, an ultrasonic test if applicable, other specified actions, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products.
At the applicable compliance times specified in paragraph (g)(1) or (2) of this AD, in accordance with Section 3.B., of the Accomplishment Instructions of De Havilland Aircraft of Canada Service Bulletin 84-53-81, Revision A, dated August 23, 2022, complete a general visual inspection of the fuselage spar frames and around the frame bolts for signs of moisture ingress (i.e., stains and streaks), accomplish other specified actions, and if necessary, perform an ultrasonic test. Do all applicable ultrasonic tests before further flight. If, during any ultrasonic test, any corrosion or structural degradation is found, before further flight, repair using a method approved by the Manager, International Validation Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada Limited's Transport Canada Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.
(1) For airplanes that, as of the effective date of this AD, have accumulated less than 32,000 total flight cycles: before accumulating 40,000 total flight cycles.
(2) For airplanes that, as of the effective date of this AD, have accumulated 32,000 or more total flight cycles: within 8,000 flight hours or 48 months, whichever occurs first after the effective date of this AD.
