Airworthiness Directives; Pratt & Whitney Division Turbofan Engines

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 the discovery of multiple cracked outer diffuser cases. This AD requires initial and repetitive inspections to detect cracks in the outer diffuser case and removal from service of cases that fail inspection. We are issuing this AD to address the unsafe condition on these products.