# Airworthiness Directives; Eurocopter Deutschland GmbH (ECD) (Eurocopter Deutschland) Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 Helicopters
> **Rule** · Final rule; request for comments. · Published 1997-12-16 · Effective 1997-12-31 · 62 FR 65750
## Document
- **Document number:** 97-32721
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 62 FR 65750
- **Publication date:** 1997-12-16
- **Effective date:** 1997-12-31
- **FAA docket:** Docket No. 97-SW-45-AD
## Abstract

This amendment adopts a new airworthiness directive (AD) that is applicable to Eurocopter Deutschland Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters. This action requires visual inspections for cracks in the ribbed area of the main rotor mast flange (flange). This amendment is prompted by one report of cracks in a flange. The actions specified in this AD are intended to detect cracks in the flange, which, if not detected, could result in failure of the flange and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1997/12/16/97-32721/airworthiness-directives-eurocopter-deutschland-gmbh-ecd-eurocopter-deutschland-model-mbb-bk-117-a-1)
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