# Proposed AD FAA-2012-0079: Pratt & Whitney Division Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-16-01
- Products: Pratt & Whitney Division
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: March 23, 2012, 77 FR 16967
- Comments due: May 22, 2012
- Became: [AD 2012-16-01](https://openairdocs.org/ad/2012-16-01)
- Docket: FAA-2012-0079 (https://www.regulations.gov/docket/FAA-2012-0079, where comments are filed)
- Project: 2012-NE-06-AD
- FR document: 2012-6965
- Official PDF: https://openairdocs.org/files/sha256/59/0a/590ac39b7a0ddda4bb87d35b2e0b6579e8d2f68e12103693d7c20934a60df262 (from https://www.govinfo.gov/content/pkg/FR-2012-03-23/pdf/2012-6965.pdf)
- Federal Register: https://www.federalregister.gov/documents/2012/03/23/2012-6965/airworthiness-directives-pratt-and-whitney-division-turbofan-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/3FDC4204F2F16F0C862579CA004C191A.0001
- Page: https://openairdocs.org/proposed/FAA-2012-0079

## Summary

We propose to adopt a new airworthiness directive (AD) for Pratt & Whitney PW4052, PW4152, PW4056, PW4156A, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4158, PW4460, PW4462, PW4164, PW4164C, PW4164C/B, PW4168, and PW4168A turbofan engines with certain high- pressure turbine (HPT) stage 1 front hubs installed. This proposed AD was prompted by Pratt & Whitney's updated low-cycle-fatigue analysis that indicated certain HPT stage 1 front hubs could initiate a crack prior to the published life limit. This proposed AD would require removing the affected HPT stage 1 front hubs from service using a drawdown plan. We are proposing this AD to prevent failure of the HPT stage 1 front hub, which could lead to an uncontained engine failure and damage to the airplane.

## Notices in this docket

- Mar 23, 2012: Notice of proposed rulemaking (NPRM). (first notice), FR document 2012-6965, comments due May 22, 2012 (https://www.federalregister.gov/documents/2012/03/23/2012-6965/airworthiness-directives-pratt-and-whitney-division-turbofan-engines)

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