# Proposed AD FAA-2013-0072: Pratt & Whitney Division Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2013-15-09
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 5, 2014, 79 FR 32500
- Comments due: August 4, 2014
- Became: [AD 2013-15-09](https://openairdocs.org/ad/2013-15-09)
- Docket: FAA-2013-0072 (https://www.regulations.gov/docket/FAA-2013-0072, where comments are filed)
- Project: 2013-NE-04-AD
- FR document: 2014-13024
- Official PDF: https://openairdocs.org/files/sha256/b4/b6/b4b68698e901bbd19daa1681bb47add3fc0382a01e528eaff211ad0f5ed19c8d (from https://www.govinfo.gov/content/pkg/FR-2014-06-05/pdf/2014-13024.pdf)
- Federal Register: https://www.federalregister.gov/documents/2014/06/05/2014-13024/airworthiness-directives-pratt-and-whitney-division-turbofan-engines
- Page: https://openairdocs.org/proposed/FAA-2013-0072

## Summary

We propose to supersede airworthiness directive (AD) 2013-15- 09, which applies to all Pratt & Whitney Division (PW) PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engine models with certain second-stage high-pressure turbine (HPT) air seals, installed. AD 2013-15-09 currently requires initial and repetitive inspections for cracks in second-stage HPT air seals. Since we issued AD 2013-15-09, we received reports of cracking in the original location on two additional part numbers (P/Ns) as well as reports of through- cracks in a new location in the second-stage HPT air seal. PW has developed a redesigned second-stage HPT air seal that addresses the cracking condition in both locations. This proposed AD would expand the applicability of AD 2013-15-09 to include additional P/Ns, require replacement of the mating hardware if the second-stage HPT air seal is found with a through-crack, and add mandatory terminating action to the repetitive inspections. We are proposing this AD to prevent failure of the second-stage HPT air seal, which could lead to uncontained engine failure and damage to the airplane.

## Notices in this docket

- Mar 18, 2013: Notice of proposed rulemaking (NPRM). (first notice), FR document 2013-06118, comments due May 17, 2013 (https://www.federalregister.gov/documents/2013/03/18/2013-06118/airworthiness-directives-pratt-and-whitney-division-turbofan-engines)
- Jun 4, 2014: Notice of proposed rulemaking (NPRM)., FR document 2014-12973, comments due Aug 4, 2014 (https://www.federalregister.gov/documents/2014/06/04/2014-12973/airworthiness-directives-pratt-and-whitney-division-turbofan-engines)
- Jun 5, 2014: Notice of proposed rulemaking (NPRM)., FR document 2014-13024, comments due Aug 4, 2014 (https://www.federalregister.gov/documents/2014/06/05/2014-13024/airworthiness-directives-pratt-and-whitney-division-turbofan-engines)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.