# Proposed AD FAA-2011-1176: Pratt & Whitney Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-06-14
- Products: Pratt & Whitney Division
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: November 23, 2011, 76 FR 72348
- Comments due: January 23, 2012
- Became: [AD 2012-06-14](https://openairdocs.org/ad/2012-06-14)
- Docket: FAA-2011-1176 (https://www.regulations.gov/docket/FAA-2011-1176, where comments are filed)
- Project: 2011-NE-35-AD
- FR document: 2011-30137
- Official PDF: https://openairdocs.org/files/sha256/3a/3f/3a3fc40991b90b38b89857e9af8a6843efe3474b5f793924f18bf5bf36a45131 (from https://www.govinfo.gov/content/pkg/FR-2011-11-23/pdf/2011-30137.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/11/23/2011-30137/airworthiness-directives-pratt-and-whitney-turbofan-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/EDCF1BC142BF2F0286257951004EF8D7.0001
- Page: https://openairdocs.org/proposed/FAA-2011-1176

## Summary

We propose to adopt a new airworthiness directive (AD) for Pratt & Whitney JT9D-7R4D, -7R4D1, -7R4E, -7R4E1, -7R4G2, -7R4H1, and - 7R4E4 turbofan engines. This proposed AD would establish a new lower life limit for high-pressure turbine (HPT) 1st stage air seals, part number (P/N) 735907, and would require removing them from service using a drawdown schedule. This proposed AD was prompted by the determination that a new lower life limit for the HPT 1st stage air seals, P/N 735907, is necessary. We are proposing this AD to prevent critical life-limited rotating engine part failure and damage to the airplane.

## Notices in this docket

- Nov 23, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-30137, comments due Jan 23, 2012 (https://www.federalregister.gov/documents/2011/11/23/2011-30137/airworthiness-directives-pratt-and-whitney-turbofan-engines)

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