# Airworthiness Directives; Leonardo S.p.a. Helicopters
> **Rule** · Final rule; request for comments. · Published 2021-04-13 · Effective 2021-04-28 · 86 FR 19127
## Document
- **Document number:** 2021-07481
- **Category:** airworthiness
- **Manufacturer:** Leonardo S.p.a.
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 86 FR 19127
- **Publication date:** 2021-04-13
- **Effective date:** 2021-04-28
- **FAA docket:** Docket No. FAA-2017-1077
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Leonardo S.p.a. Model AB412 helicopters. This AD was prompted by a cracked spiral bevel gear. This AD requires a one-time visual inspection and a recurring fluorescent magnetic particle inspection (FMPI) of affected spiral bevel gears for a crack, and depending on the inspection results, removing the spiral bevel gear from service. This AD also prohibits installing an affected spiral bevel gear unless it has recently passed an FMPI. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2021/04/13/2021-07481/airworthiness-directives-leonardo-spa-helicopters)
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