# Proposed AD FAA-2013-0766: Pratt & Whitney Canada Corp. Turboprop Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2014-17-08
- Products: Pratt & Whitney Canada
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: December 1, 2014, 79 FR 71031
- Comments due: January 30, 2015
- Became: [AD 2014-17-08](https://openairdocs.org/ad/2014-17-08)
- Docket: FAA-2013-0766 (https://www.regulations.gov/docket/FAA-2013-0766, where comments are filed)
- Project: 2013-NE-26-AD
- FR document: 2014-28188
- Official PDF: https://openairdocs.org/files/sha256/ef/4d/ef4dd63b9794ad7e76fea35a44468d4f2bb5e54564e1f5caf3cab376e71c7003 (from https://www.govinfo.gov/content/pkg/FR-2014-12-01/pdf/2014-28188.pdf)
- Federal Register: https://www.federalregister.gov/documents/2014/12/01/2014-28188/airworthiness-directives-pratt-and-whitney-canada-corp-turboprop-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1A4A48BD3B984C4186257DA1004C93D6.0001
- Page: https://openairdocs.org/proposed/FAA-2013-0766

## Summary

We propose to revise airworthiness directive (AD) 2014-17-08 that applies to all Pratt & Whitney Canada Corp. (P&WC) PT6A-114 and PT6A-114A turboprop engines. AD 2014-17-08 requires initial and repetitive borescope inspections (BSIs) of compressor turbine (CT) blades, and the removal from service of blades that fail inspection. Since we issued AD 2014-17-08, P&WC developed an additional single crystal CT blade that corrects the unsafe condition. This proposed AD would retain all the requirements of AD 2014-17-08, add an additional single crystal CT blade that corrects the unsafe condition, reduce the affected population, and correct the Credit for Previous Action paragraph. We are proposing this AD to prevent failure of CT blades, which could result in damage to the engine and damage to the airplane.

## Notices in this docket

- Oct 29, 2013: Notice of proposed rulemaking (NPRM). (first notice), FR document 2013-25460, comments due Dec 30, 2013 (https://www.federalregister.gov/documents/2013/10/29/2013-25460/airworthiness-directives-pratt-and-whitney-canada-corp-turboprop-engines)
- May 12, 2014: Supplemental notice of proposed rulemaking (NPRM); request for comments., FR document 2014-09929, comments due Jun 26, 2014 (https://www.federalregister.gov/documents/2014/05/12/2014-09929/airworthiness-directives-pratt-and-whitney-canada-corp-turboprop-engines)
- Dec 1, 2014: Notice of proposed rulemaking (NPRM)., FR document 2014-28188, comments due Jan 30, 2015 (https://www.federalregister.gov/documents/2014/12/01/2014-28188/airworthiness-directives-pratt-and-whitney-canada-corp-turboprop-engines)

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