# Airworthiness Directives; Various Restricted Category Helicopters
> **Rule** · Final rule. · Published 2016-11-22 · Effective 2016-12-27 · 81 FR 83660
## Document
- **Document number:** 2016-27767
- **Category:** airworthiness
- **Manufacturer:** Various Restricted Category
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 81 FR 83660
- **Publication date:** 2016-11-22
- **Effective date:** 2016-12-27
- **FAA docket:** Docket No. FAA-2015-3820
## Abstract

We are adopting a new airworthiness directive (AD) for various restricted category helicopters. This AD requires cleaning and visually inspecting certain main rotor (M/R) blades and, depending on the outcome of the inspections, repairing or replacing the M/R blades. This AD was prompted by a report of an M/R blade with multiple fatigue cracks around the blade retention bolt hole. The actions are intended to detect a crack in the M/R blade, and prevent failure of the M/R blade and subsequent loss of helicopter control.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2016/11/22/2016-27767/airworthiness-directives-various-restricted-category-helicopters)
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