Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-400 series airplanes. This proposed AD was prompted by a report of broken P-clamps on the pressure relief line and the motive flow line in the left and right fuel tanks, and fouling conditions between the motive flow line and the collector tank partition wall in both fuel tanks. This proposed AD would require, depending on airplane configuration: Increasing the hole size in the collector tank partition wall, inspecting the motive flow line for damage, and replacing the associated grommet and motive flow line; replacing the affected single nut plate brackets and standoffs at the affected stations on the motive flow line and pressure relief line; and inspecting the motive flow line and vent line at certain wing stations, and inspecting the fuel tubes, to verify that an appropriate clearance has been maintained between the fuel tubes and their support brackets, and applicable corrective actions. We are proposing this AD to address the unsafe condition on these products.