# Proposed AD FAA-2015-1998: MD Helicopters Inc.

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2016-01-19
- Products: MD Helicopters
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 9, 2015, 80 FR 32508
- Comments due: August 10, 2015
- Became: [AD 2016-01-19](https://openairdocs.org/ad/2016-01-19)
- Docket: FAA-2015-1998 (https://www.regulations.gov/docket/FAA-2015-1998, where comments are filed)
- Project: 2014-SW-035-AD
- FR document: 2015-13853
- Official PDF: https://openairdocs.org/files/sha256/49/0a/490ac0f1514d85a6bdbea1833e481fcc4a1cb87b43edb54a96af7f7ceb83d8f3 (from https://www.govinfo.gov/content/pkg/FR-2015-06-09/pdf/2015-13853.pdf)
- Federal Register: https://www.federalregister.gov/documents/2015/06/09/2015-13853/airworthiness-directives-md-helicopters-inc
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B3EA9935238074E286257E5F0049B535.0001
- Page: https://openairdocs.org/proposed/FAA-2015-1998

## Summary

We propose to adopt a new airworthiness directive (AD) for MD Helicopters Inc. (MDHI) Model 500N and 600N helicopters with certain rotating cone assemblies installed. This proposed AD would require establishing a life limit of 10,000 hours time-in-service (TIS) on these rotating cone assemblies. This proposed AD is prompted by the determination that MDHI created rotating cone assemblies with new dash numbers but incorrectly failed to identify them as life-limited parts. The proposed actions are intended to prevent operation of rotating cone assemblies past their life limits, failure of the rotating cone assemblies, loss of directional control, and subsequent loss of control of the helicopter.

## Notices in this docket

- Jun 9, 2015: Notice of proposed rulemaking (NPRM). (first notice), FR document 2015-13853, comments due Aug 10, 2015 (https://www.federalregister.gov/documents/2015/06/09/2015-13853/airworthiness-directives-md-helicopters-inc)

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