Airworthiness Directives; Pratt & Whitney Canada Corp. Engines

The FAA proposes to adopt a new airworthiness directive (AD) for certain Pratt & Whitney Canada Corp. (P&WC) Model PW535E and PW535E1 engines. This proposed AD was prompted by a manufacturer design review that indicated certain flange bolts securing the gas generator case and turbine support case are susceptible to cracking at their current low-cycle fatigue (LCF) life. This proposed AD would require repetitive borescope inspections (BSI) of the gas generator case to turbine support case retaining bolts for evidence of bolt cracks, bolt fracture, missing bolts, or loose bolts and replacement, if necessary, as specified in a Transport Canada AD, which is incorporated by reference. The FAA is proposing this AD to address the unsafe condition on these products.