Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-401 and -402 airplanes. This proposed AD was prompted by a discovery of cracking on two test spoiler power control unit (PCU) manifolds during testing by the manufacturer. This proposed AD would require replacement of affected spoiler PCUs. We are proposing this AD to prevent cracking of the spoiler PCUs that could lead to the loss of multiple flight controls and landing gear systems.