# Airworthiness Directives; Bell Helicopter Textron Canada (Bell) Helicopters
> **Rule** · Final rule. · Published 2015-08-20 · Effective 2015-09-24 · 80 FR 50550
## Document
- **Document number:** 2015-20509
- **Category:** airworthiness
- **Manufacturer:** Bell Helicopter Textron Canada (Bell)
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 80 FR 50550
- **Publication date:** 2015-08-20
- **Effective date:** 2015-09-24
- **FAA docket:** Docket No. FAA-2014-0643
## Abstract

We are superseding Airworthiness Directive (AD) 2001-13-51 for Bell Model 206L-4, 407, and 427 helicopters. AD 2001-13-51 required inspecting certain driveshafts for a crack, a loose bolt or nut, or red powder residue and replacing a driveshaft if there is a crack, a loose bolt or nut, or red powder residue. AD 2001-13-51 also required notifying the FAA within 10 days if a crack is found in the driveshaft. This new AD retains the inspection requirement of AD 2001-13-51, expands the applicability to include the Model 429 helicopter, and removes the reporting requirement. This AD is intended to prevent failure of a driveshaft, loss of drive to the main rotor system, and a subsequent emergency landing.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2015/08/20/2015-20509/airworthiness-directives-bell-helicopter-textron-canada-bell-helicopters)
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