# Airworthiness Directives; Eurocopter Deutschland GMBH Model MBB-BK 117 Helicopters
> **Rule** · Final rule. · Published 2000-03-24 · 65 FR 15858
## Document
- **Document number:** 00-7336
- **Category:** airworthiness
- **Manufacturer:** Eurocopter Deutschland GMBH Model MBB-BK 117
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 65 FR 15858
- **Publication date:** 2000-03-24
- **FAA docket:** Docket No. 98-SW-77-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to Eurocopter Deutschland GMBH (ECD) Model MBB-BK 117 helicopters, that requires changing the retirement life for the tail rotor (output) drive bevel gear (bevel gear). This amendment is prompted by a fatigue analysis of the bevel gear conducted by the manufacturer due to installation of different tail rotor blades. The actions specified by this AD are intended to prevent fatigue failure of the bevel gear, loss of tail rotor drive, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2000/03/24/00-7336/airworthiness-directives-eurocopter-deutschland-gmbh-model-mbb-bk-117-helicopters)
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