# Airworthiness Directives Eurocopter France (ECF) Model SA-365N1, AS-365N2, AS 365 N3, EC 155B, and EC155B1 Helicopters
> **Rule** · Final rule. · Published 2010-09-22 · Effective 2010-10-27 · 75 FR 57659
## Document
- **Document number:** 2010-23098
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 75 FR 57659
- **Publication date:** 2010-09-22
- **Effective date:** 2010-10-27
- **FAA docket:** Docket No. FAA-2010-0426
## Abstract

We are adopting a new airworthiness directive (AD) for the specified ECF model helicopters. This AD results from a mandatory continuing airworthiness information (MCAI) AD issued by the aviation authority of the European Aviation Safety Agency (EASA). The MCAI AD reports the separation and loss of a stainless steel ring (75 millimeter (mm) in diameter) from a tail rotor blade (blade) sleeve resulting in severe, high-frequency vibrations, which can lead to damage to the fenestron blades, loss of yaw control, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2010/09/22/2010-23098/airworthiness-directives-eurocopter-france-ecf-model-sa-365n1-as-365n2-as-365-n3-ec-155b-and-ec155b1)
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