Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-401 and -402 airplanes. This AD was prompted by the discovery of cracking on two test spoiler power control unit (PCU) manifolds during testing by the manufacturer. This AD requires replacement of affected spoiler PCUs. We are issuing this AD to address the unsafe condition on these products.