# Airworthiness Directives; Various Restricted Category Helicopters
> **Rule** · Final rule; request for comments. · Published 2012-09-13 · Effective 2012-09-28 · 77 FR 56528
## Document
- **Document number:** 2012-22564
- **Category:** airworthiness
- **Manufacturer:** Various Restricted Category
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 77 FR 56528
- **Publication date:** 2012-09-13
- **Effective date:** 2012-09-28
- **FAA docket:** Docket No. FAA-2012-0896
## Abstract

We are adopting a new airworthiness directive (AD) for various restricted category Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH- 1F, UH-1H, UH-1L, and UH-1P helicopters with certain main rotor (M/R) blade assemblies installed, to require inspecting the grip plates, doublers, and upper and lower surfaces of the M/R blades in the area between blade stations 24.5 and 40 for an edge void, corrosion, or a crack. This AD is prompted by several reports of fatigue cracks on M/R blades installed on Bell Helicopter Textron, Inc. (Bell) Model 212 helicopters. These same part-numbered M/R blades may also be installed on certain FAA-approved modified restricted category helicopters. These actions are intended to detect an edge void, corrosion, or a crack on an M/R blade, which could lead to loss of the M/R blade and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2012/09/13/2012-22564/airworthiness-directives-various-restricted-category-helicopters)
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