Superseded. This AD was superseded by AD 2023-19-02. Verify which one applies to your serial and effectivity before any maintenance action.
AD 2018-21-11
Effective 12/05/2018 · Published 10/31/2018
Airworthiness Directives; Pratt & Whitney Division (PW) Turbofan Engines
Summary
We are adopting a new airworthiness directive (AD) for all Pratt & Whitney Division (PW) PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines with a low-pressure compressor (LPC) fan hub, part number (P/N) 51B821 or P/N 52B521, installed. This AD was prompted by updated low-cycle fatigue analysis techniques that indicate certain LPC fan hubs could crack before their published life limit. This AD requires…