# Airworthiness Directives; Pratt & Whitney Canada Turboprop Engines
> **Rule** · Final rule; request for comments. · Published 2012-05-08 · Effective 2012-05-23 · 77 FR 26943
## Document
- **Document number:** 2012-11057
- **Category:** airworthiness
- **Manufacturer:** Pratt & Whitney Canada Turboprop
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 77 FR 26943
- **Publication date:** 2012-05-08
- **Effective date:** 2012-05-23
- **FAA docket:** Docket No. FAA-2012-0417
## Abstract

We are adopting a new airworthiness directive (AD) for certain Pratt & Whitney Canada PT6A-38, -41, -42, -42A, -61, -64, -66, -66B, - 110, -112, -114, -114A, -121, -135, and -135A series turboprop engines. This AD requires removal from service of certain part manufacturer approval (PMA) replacement Timken Alcor Aerospace Technologies, Inc. (TAATI) first stage sun gears and planet gears installed in the reduction gearbox. This AD was prompted by failures of certain first stage sun gears manufactured by TAATI. We are issuing this AD to prevent failure of the sun gear and planet gears 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/2012/05/08/2012-11057/airworthiness-directives-pratt-and-whitney-canada-turboprop-engines)
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