# Proposed AD 96-SW-23-AD: Eurocopter Deutschland GmbH Model MBB- BK 117 A-1, A-3, A-4, B-1, B-2 and C-1 Helicopters

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 97-23-07
- Action: Notice of proposed rulemaking (NPRM).
- Published: February 4, 1997, 62 FR 5186
- Comments due: April 7, 1997
- Became: [AD 97-23-07](https://openairdocs.org/ad/97-23-07)
- Docket: 96-SW-23-AD
- FR document: 97-2720
- Official PDF: https://openairdocs.org/files/sha256/05/b9/05b94df3b588a39d987dc4a2d72e999876bae906d963b0ef87ae1156d1d39037 (from https://www.govinfo.gov/content/pkg/FR-1997-02-04/pdf/97-2720.pdf)
- Federal Register: https://www.federalregister.gov/documents/1997/02/04/97-2720/airworthiness-directives-eurocopter-deutschland-gmbh-model-mbb--bk-117-a-1-a-3-a-4-b-1-b-2-and-c-1
- Page: https://openairdocs.org/proposed/96-SW-23-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Eurocopter Deutschland GmbH (Eurocopter) Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters. This proposal would establish a new retirement life for the clutch and would require an entry into the Accessory Replacement Record indicating the new life limit. This proposal is prompted by a recalculation of life limitations by the part manufacturer, Warner Electric. The clutch manufacturer used the airframe load spectrum to establish the new life limit of 3,600 hours time-in-service (TIS). The actions specified by the proposed AD are intended to prevent failure of the clutch, loss of power to the main rotor and a subsequent forced landing of the helicopter.

## Notices in this docket

- Feb 4, 1997: Notice of proposed rulemaking (NPRM). (first notice), FR document 97-2720, comments due Apr 7, 1997 (https://www.federalregister.gov/documents/1997/02/04/97-2720/airworthiness-directives-eurocopter-deutschland-gmbh-model-mbb--bk-117-a-1-a-3-a-4-b-1-b-2-and-c-1)

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