# Airworthiness Directives; Pratt & Whitney Canada Turboprop Engines
> **Rule** · Final rule; request for comments. · Published 2011-12-13 · Effective 2011-12-28 · 76 FR 77380
## Document
- **Document number:** 2011-31868
- **Category:** airworthiness
- **Manufacturer:** Pratt & Whitney Canada Turboprop
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 76 FR 77380
- **Publication date:** 2011-12-13
- **Effective date:** 2011-12-28
- **FAA docket:** Docket No. FAA-2011-1298
## Abstract

We are adopting a new airworthiness directive (AD) for Pratt & Whitney Canada PT6A-15AG, -27, -28, -34, -34AG, -34B, and -36 series turboprop engines. This AD requires the removal of certain affected part manufacturer approval (PMA) replacement Timken Alcor Aerospace Technologies, Inc. (TAATI) first stage reduction sun gears and/or the interacting planetary gear sets from the propeller reduction gearbox assembly. This AD was prompted by a failure report of a certain TAATI PMA sun gear, installed since December 22, 2008. We are issuing this AD to prevent failure of the sun gear, which will result in an engine in- flight shut down, possible uncontained engine failure, aircraft damage, and serious injuries.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2011/12/13/2011-31868/airworthiness-directives-pratt-and-whitney-canada-turboprop-engines)
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