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 certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by reports of broken P-clamps on the pressure relief line and the motive flow line in the fuel tanks, and a subsequent determination that certain service information lacked instructions for maintaining appropriate clearance between certain fuel tubes and their support brackets, and may also have led to incorrect installation of certain Teflon<SUP>TM</SUP> sleeves. This AD was also prompted by a determination that new or more restrictive airworthiness limitations are necessary. This AD requires inspecting the motive flow line, vent line, and related parts, and adding support or additional clearance if necessary. This AD also requires inspection, and replacement or relocation if necessary, of affected Teflon<SUP>TM</SUP> sleeves on the vent line, and installation of Teflon<SUP>TM</SUP> sleeves on the vent line at additional wing stations. This AD also requires revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive airworthiness limitations. The FAA is issuing this AD to address the unsafe condition on these products.