# Proposed AD FAA-2006-24034: Pratt & Whitney PW4077D, PW4084D, PW4090, and PW4090-3 Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2006-17-08
- Products: Pratt & Whitney
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: November 20, 2006, 71 FR 67073
- Comments due: January 19, 2007
- Became: [AD 2006-17-08](https://openairdocs.org/ad/2006-17-08)
- Docket: FAA-2006-24034 (https://www.regulations.gov/docket/FAA-2006-24034, where comments are filed)
- Project: 2006-NE-05-AD
- FR document: E6-19536
- Official PDF: https://openairdocs.org/files/sha256/ad/74/ad7475afd9b400f728f82ae80d4214930318ceaa0d27fb8dec85c719170d75e4 (from https://www.govinfo.gov/content/pkg/FR-2006-11-20/pdf/E6-19536.pdf)
- Federal Register: https://www.federalregister.gov/documents/2006/11/20/E6-19536/airworthiness-directives-pratt-and-whitney-pw4077d-pw4084d-pw4090-and-pw4090-3-turbofan-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D06B6AE54F6A5BBC8625722C005B1DF6.0001
- Page: https://openairdocs.org/proposed/FAA-2006-24034

## Summary

The FAA proposes to supersede an existing airworthiness directive (AD) for Pratt & Whitney PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines that were reassembled with previously used high pressure compressor (HPC) exit brush seal packs and new or refurbished HPC exit diffuser air seal lands. That AD currently requires replacing the HPC exit inner and outer brush seal packs with new brush seal packs, or replacing the HPC exit brush seal assembly with a new HPC exit brush seal assembly. This proposed AD would require replacing the HPC exit inner and outer brush seal packs with new brush seal packs, using either original equipment manufactured (OEM) parts, or FAA-approved part manufacturer approval (PMA) equivalent parts. This proposed AD would also apply to engines reassembled with a PMA equivalent HPC exit inner and/or outer brush seal packs. This proposed AD results from a request to include PMA equivalent HPC exit inner and outer brush seal packs and to include the engines with PMA equivalent parts already installed, in the AD. We are proposing this AD to prevent uncontained engine failure, damage to the airplane, and injury to passengers.

## Notices in this docket

- Apr 19, 2006: Notice of proposed rulemaking (NPRM). (first notice), FR document E6-5843, comments due Jun 19, 2006 (https://www.federalregister.gov/documents/2006/04/19/E6-5843/airworthiness-directives-pratt-and-whitney-pw4077d-pw4084d-pw4090-and-pw4090-3-turbofan-engines)
- Nov 20, 2006: Notice of proposed rulemaking (NPRM)., FR document E6-19536, comments due Jan 19, 2007 (https://www.federalregister.gov/documents/2006/11/20/E6-19536/airworthiness-directives-pratt-and-whitney-pw4077d-pw4084d-pw4090-and-pw4090-3-turbofan-engines)

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