# Airworthiness Directives; Various Restricted Category Helicopters
> **Rule** · Final rule; request for comments. · Published 2013-07-09 · Effective 2013-07-24 · 78 FR 40954
## Document
- **Document number:** 2013-15946
- **Category:** airworthiness
- **Manufacturer:** Various Restricted Category
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 78 FR 40954
- **Publication date:** 2013-07-09
- **Effective date:** 2013-07-24
- **FAA docket:** Docket No. FAA-2013-0553
## 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 hub inboard strap fittings (fittings) installed. This AD requires a magnetic particle inspection (MPI) of the fittings for a crack, and if there is a crack, replacing the fitting with an airworthy fitting. This AD is prompted by reports of cracked fittings on Bell model helicopters and the determination that these same part-numbered fittings may be installed on various restricted category helicopters. These actions are intended to detect a crack in a fitting, which may lead to failure of a fitting, loss of a main rotor blade, and subsequent loss of helicopter control.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2013/07/09/2013-15946/airworthiness-directives-various-restricted-category-helicopters)
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