# Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) Helicopters
> **Rule** · Final rule. · Published 2013-10-31 · Effective 2013-12-05 · 78 FR 65206
## Document
- **Document number:** 2013-24035
- **Category:** airworthiness
- **Manufacturer:** Bell Helicopter Textron Canada Limited (Bell)
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 78 FR 65206
- **Publication date:** 2013-10-31
- **Effective date:** 2013-12-05
- **FAA docket:** Docket No. FAA-2013-0491
## Abstract

We are adopting a new airworthiness directive (AD) for certain Bell Model 430 helicopters. This AD requires installing a placard on the instrument panel and revising the limitations section of the rotorcraft flight manual (RFM). This AD was prompted by several incidents of third stage engine turbine wheel failures, which were caused by excessive vibrations at certain engine speeds during steady- state operations. These actions are intended to alert pilots to avoid certain engine speeds during steady-state operations, prevent failure of the third stage engine turbine, engine power loss, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2013/10/31/2013-24035/airworthiness-directives-bell-helicopter-textron-canada-limited-bell-helicopters)
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