Airworthiness Directive · Amendment 39-21981 · Pneumatic
De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
This AD applies to all De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Model DHC-8-401 and -402 airplanes, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This AD was prompted by reports of bleed air leaks in the wing box area and failure of the leak detection shroud. This AD requires removing and inspecting the affected V-band coupling and check valve seals, doing corrective actions if necessary, and replacing the coupling and seals with a redesigned assembly. The FAA is issuing this AD to address the unsafe condition on these products.
Within 48 months or 8,000 flight hours, whichever occurs first, from the effective date of this AD: Remove the affected V-band coupling and check valve seals, do a visual inspection for damage to the coupling covers and surrounding area, and replace the coupling and seals with a redesigned assembly, in accordance with the Accomplishment Instructions, paragraph 3.B., of de Havilland Service Bulletin 84-36-06, dated December 15, 2020.
(1) If any damage to a coupling cover is found, replace the coupling cover before further flight in accordance with the Accomplishment Instructions of de Havilland Service Bulletin 84-36-06, dated December 15, 2020.
(2) If any damage to the surrounding area is found, before further flight, accomplish corrective actions in accordance with the procedures specified in paragraph (i)(2) of this AD.
