Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for all Pratt & Whitney Division (PW) PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines. This AD was prompted by an uncontained failure of a high-pressure turbine (HPT) hub during takeoff. This AD requires an inspection to measure the surface condition of the aft side web/rim fillet of HPT 1st stage hubs and removal from service of hubs that fail inspection. We are issuing this AD to correct the unsafe condition on these products.