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

The FAA proposes to adopt a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This proposed AD was prompted by multiple in-service reports of cracks in elevator power control unit (PCU) brackets (fittings) and the elevator front spar. This proposed AD would require replacing bushings and installing new washers on the elevator PCU arm fitting assembly, installing doublers at the front spar of the elevator structure assembly, replacing horizontal stabilizer rear spar elevator PCU fittings, and applicable on-conditions actions. The FAA is proposing this AD to address the unsafe condition on these products.