# Proposed AD FAA-2011-0733: Pratt & Whitney Division (PW) PW4000 Series Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2011-25-09
- Products: Pratt & Whitney Division
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: July 14, 2011, 76 FR 41430
- Comments due: August 29, 2011
- Became: [AD 2011-25-09](https://openairdocs.org/ad/2011-25-09)
- Docket: FAA-2011-0733 (https://www.regulations.gov/docket/FAA-2011-0733, where comments are filed)
- Project: 2010-NE-36-AD
- FR document: 2011-17648
- Official PDF: https://openairdocs.org/files/sha256/db/95/db95af94d8d0330b9aa89947edc90b7b99e45ef6b435782fc3a3a482f2383c38 (from https://www.govinfo.gov/content/pkg/FR-2011-07-14/pdf/2011-17648.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/07/14/2011-17648/airworthiness-directives-pratt-and-whitney-division-pw-pw4000-series-turbofan-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9CA6F3A811185718862578CD0049E3AF.0001
- Page: https://openairdocs.org/proposed/FAA-2011-0733

## Summary

We propose to adopt a new airworthiness directive (AD) for certain PW4000 turbofan engines. This proposed AD was prompted by an updated low-cycle fatigue (LCF) life analysis performed by Pratt & Whitney. This proposed AD would require removing certain part number (P/N) high-pressure turbine (HPT) stage 1 and HPT stage 2 airseals and HPT stage 1 airseal rings before their published life limit, and establishes a new lower life limit for these parts. We are proposing this AD to correct the unsafe condition on these products.

## Notices in this docket

- Jul 14, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-17648, comments due Aug 29, 2011 (https://www.federalregister.gov/documents/2011/07/14/2011-17648/airworthiness-directives-pratt-and-whitney-division-pw-pw4000-series-turbofan-engines)

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