# Proposed AD FAA-2016-7850: Turbomeca S.A. Turboshaft Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2017-05-08
- Products: Turbomeca
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: November 4, 2016, 81 FR 76885
- Comments due: December 19, 2016
- Became: [AD 2017-05-08](https://openairdocs.org/ad/2017-05-08)
- Docket: FAA-2016-7850 (https://www.regulations.gov/docket/FAA-2016-7850, where comments are filed)
- Project: 2016-NE-16-AD
- FR document: 2016-26335
- Official PDF: https://openairdocs.org/files/sha256/dc/8c/dc8c0a6ac72e9902db9dbdb6ed79ed075b33a4746c2ef4dfc6eb5a4999a87f89 (from https://www.govinfo.gov/content/pkg/FR-2016-11-04/pdf/2016-26335.pdf)
- Federal Register: https://www.federalregister.gov/documents/2016/11/04/2016-26335/airworthiness-directives-turbomeca-sa-turboshaft-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/682DE3561D0F415A862580610050D9E1.0001
- Page: https://openairdocs.org/proposed/FAA-2016-7850

## Summary

We propose to adopt a new airworthiness directive (AD) for all Turbomeca S.A. Arriel 2B turboshaft engines. This proposed AD was prompted by a report of an uncommanded in-flight shutdown (IFSD) on a single-engine helicopter, caused by a low returning spring rate of the needle of the hydro-mechanical metering unit (HMU). This proposed AD would require removing any pre-modification (mod) TU 158 HMU and replacing with a part eligible for installation. We are proposing this AD to prevent failure of the HMU, failure of the engine, IFSD, and loss of the helicopter.

## Notices in this docket

- Nov 4, 2016: Notice of proposed rulemaking (NPRM). (first notice), FR document 2016-26335, comments due Dec 19, 2016 (https://www.federalregister.gov/documents/2016/11/04/2016-26335/airworthiness-directives-turbomeca-sa-turboshaft-engines)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.