# Airworthiness Directives; Rolls-Royce Corporation (Formerly Allison Engine Company) 501-D22A, 501-D22C, and 501-D22G Turboprop Engines
> **Rule** · Final rule. · Published 2005-10-25 · Effective 2005-11-29 · 70 FR 61549
## Document
- **Document number:** 05-21173
- **Category:** airworthiness
- **Manufacturer:** Rolls-Royce Corporation (Formerly Allison
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 70 FR 61549
- **Publication date:** 2005-10-25
- **Effective date:** 2005-11-29
- **FAA docket:** Docket No. FAA-2005-20742
## Abstract

The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce Corporation (RRC) (formerly Allison Engine Company) 501- D22A, 501-D22C, and 501-D22G turboprop engines. This AD requires a onetime inspection for proper metal hardness of certain 1st stage, 2nd stage, 3rd stage, and 4th stage turbine wheels. This AD results from a report of a turbine wheel found to be over dimensional limits, caused by improper metal hardness. We are issuing this AD to prevent uncontained turbine wheel failure, leading to damage of the airplane and total loss of engine power.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2005/10/25/05-21173/airworthiness-directives-rolls-royce-corporation-formerly-allison-engine-company-501-d22a-501-d22c)
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