# Airworthiness Directives; Eurocopter France Model AS-365N2, AS 365 N3, EC 155B, EC155B1, SA-365N and N1, and SA-366G1 Helicopters
> **Rule** · Final rule; request for comments. · Published 2004-08-19 · Effective 2004-09-03 · 69 FR 51358
## Document
- **Document number:** 04-18438
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 69 FR 51358
- **Publication date:** 2004-08-19
- **Effective date:** 2004-09-03
- **FAA docket:** Docket No. FAA-2004-18850
## Abstract

This amendment adopts a new airworthiness directive (AD) for the specified Eurocopter France (Eurocopter) helicopters. This action requires inspecting the main gearbox (MGB) baseplate for a crack and replacing the MGB if a crack is found in the MGB base plate. This amendment is prompted by the discovery of a crack in a MGB base plate. The actions specified in this AD are intended to detect a crack in a MGB base plate and prevent failure of one of the MGB attachment points to the frame, which could result in severe vibration and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2004/08/19/04-18438/airworthiness-directives-eurocopter-france-model-as-365n2-as-365-n3-ec-155b-ec155b1-sa-365n-and-n1)
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