# Airworthiness Directives; Agusta Model A109A, A109AII, and A109C Helicopters
> **Rule** · Final rule; request for comments. · Published 2000-04-14 · Effective 2000-05-01 · 65 FR 20081
## Document
- **Document number:** 00-9359
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 65 FR 20081
- **Publication date:** 2000-04-14
- **Effective date:** 2000-05-01
- **FAA docket:** Docket No. 99-SW-47-AD
## Abstract

This amendment adopts a new airworthiness directive (AD) applicable to Agusta Model A109A, A109AII, and A109C helicopters. This action requires inspecting the main transmission to determine if certain Gleason crowns are installed and replacing any unairworthy Gleason crown with an airworthy Gleason crown. This amendment is prompted by the discovery of a cracked Gleason crown during an unscheduled transmission inspection prompted by abnormal noises coming from the transmission during main rotor deceleration. The actions specified in this AD are intended to prevent failure of the main transmission, loss of rotor drive, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2000/04/14/00-9359/airworthiness-directives-agusta-model-a109a-a109aii-and-a109c-helicopters)
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