# Proposed AD FAA-2018-0368: Pratt & Whitney Division (PW) Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2018-21-11
- Products: Pratt & Whitney Division
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: July 19, 2018, 83 FR 34070
- Comments due: September 4, 2018
- Became: [AD 2018-21-11](https://openairdocs.org/ad/2018-21-11)
- Docket: FAA-2018-0368 (https://www.regulations.gov/docket/FAA-2018-0368, where comments are filed)
- FR document: 2018-15291
- Official PDF: https://openairdocs.org/files/sha256/22/50/225033797b7a7d89cc6d1cbe4a6f46894ff55a78fb475d16be7d883279610ff0 (from https://www.govinfo.gov/content/pkg/FR-2018-07-19/pdf/2018-15291.pdf)
- Federal Register: https://www.federalregister.gov/documents/2018/07/19/2018-15291/airworthiness-directives-pratt-and-whitney-division-pw-turbofan-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/91195B7B427BD85F862582CF0055DF21.0001
- Page: https://openairdocs.org/proposed/FAA-2018-0368

## Summary

We propose to adopt 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 proposed AD was prompted by updated low cycle fatigue analysis techniques that indicate certain LPC fan hubs could crack prior to their published life limit. This proposed AD would require repetitive eddy current inspections (ECIs) and fluorescent penetrant inspections (FPIs) for cracks in certain LPC fan hubs and removal of hubs from service that fail inspection. We are proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Jul 19, 2018: Notice of proposed rulemaking (NPRM). (first notice), FR document 2018-15291, comments due Sep 4, 2018 (https://www.federalregister.gov/documents/2018/07/19/2018-15291/airworthiness-directives-pratt-and-whitney-division-pw-turbofan-engines)

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