# Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) Helicopters
> **Rule** · Final rule. · Published 2018-05-21 · Effective 2018-06-25 · 83 FR 23349
## Document
- **Document number:** 2018-10491
- **Category:** airworthiness
- **Manufacturer:** Bell Helicopter Textron Canada Limited (Bell)
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 83 FR 23349
- **Publication date:** 2018-05-21
- **Effective date:** 2018-06-25
- **FAA docket:** Docket No. FAA-2017-0667
## Abstract

We are adopting a new airworthiness directive (AD) for Bell Model 407 helicopters. This AD requires repetitive inspections of the tail rotor (TR) driveshaft segment assemblies and a torque check of the TR adapter retention nuts. This AD was prompted by a report of an in- flight failure of the TR drive system. The actions of this AD are intended to detect and correct an unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2018/05/21/2018-10491/airworthiness-directives-bell-helicopter-textron-canada-limited-bell-helicopters)
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