Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

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.