# Airworthiness Directives; Bell Helicopter Textron Canada Helicopters
> **Rule** · Final rule. · Published 2013-06-27 · Effective 2013-08-01 · 78 FR 38546
## Document
- **Document number:** 2013-14857
- **Category:** airworthiness
- **Manufacturer:** Bell Helicopter Textron Canada
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 78 FR 38546
- **Publication date:** 2013-06-27
- **Effective date:** 2013-08-01
- **FAA docket:** Docket No. FAA-2013-0019
## Abstract

We are adopting a new airworthiness directive (AD) for Bell Helicopter Textron Canada (BHTC) Model 407 helicopters with certain tailboom assemblies installed. This AD requires, at specified intervals, inspecting the tailboom assembly for a crack, loose rivet, or other damage. This AD was prompted by a stress analysis of the tailboom skin that revealed that high-stress-concentration areas are susceptible to skin cracking. This condition, if not detected, could result in a crack in the tailboom assembly, failure of the tailboom, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2013/06/27/2013-14857/airworthiness-directives-bell-helicopter-textron-canada-helicopters)
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