Action
Notice of proposed rulemaking (NPRM).
Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2019-03-01 and AD 2021-05-51, which apply to certain Pratt & Whitney Division (PW) PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 model turbofan engines. AD 2019-03-01 requires performing initial and repetitive thermal acoustic image (TAI) inspections for cracks in certain 1st-stage low-pressure compressor (LPC) blades and removal of those blades that fail inspection. AD 2021-05-51 requires performing a one-time TAI inspection for cracks in certain 1st-stage LPC blades and removal of those blades that fail inspection. Since the FAA issued AD 2019-03-01 and AD 2021-05-51, the manufacturer determined the need to add initial and repetitive ultrasonic testing (UT) inspections of the 1st-stage LPC blades. This proposed AD would require initial and repetitive UT inspections and TAI inspections for cracks in certain 1st-stage LPC blades and removal of those blades that fail inspection. The FAA is proposing this AD to address the unsafe condition on these products.