AD NUMBER: 2018-21-11

PRODUCT: 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.

ACTION: Final Rule.

SUMMARY: 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 repetitive eddy current inspections(ECIs) and fluorescent penetrant inspections (FPIs) for cracks in certain LPC fan hubs and removal ofLPC fan hubs from service that fail inspection.

DATES: This AD is effective December 5, 2018.

COST: The FAA estimates that this AD affects 32 engines installed on airplanes of U.S. registry. Operators may incur the following costs in order to comply with this AD:

• Inspection - 40 work-hours × $85 per hour =$3,400 per engine
• Replace the LPC fan hub (prorated part cost). Parts - $288,000. Cost per Engine - $288,000.

FMI: AD