# Proposed AD FAA-2007-27009: Turbomeca S.A. Turboshaft Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2007-03-14
- Products: Turbomeca
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: December 24, 2013, 78 FR 77614
- Comments due: February 24, 2014
- Became: [AD 2007-03-14](https://openairdocs.org/ad/2007-03-14)
- Docket: FAA-2007-27009 (https://www.regulations.gov/docket/FAA-2007-27009, where comments are filed)
- Project: 2007-NE-02-AD
- FR document: 2013-30488
- Official PDF: https://openairdocs.org/files/sha256/d4/0f/d40f3f69894f9ad94e66b570c853b3393f602148319a7c346a5b97bbc6856c28 (from https://www.govinfo.gov/content/pkg/FR-2013-12-24/pdf/2013-30488.pdf)
- Federal Register: https://www.federalregister.gov/documents/2013/12/24/2013-30488/airworthiness-directives-turbomeca-sa-turboshaft-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1A647C779C05535B86257C4B004FD596.0001
- Page: https://openairdocs.org/proposed/FAA-2007-27009

## Summary

We propose to supersede airworthiness directive (AD) 2007-19- 09R1 that applies to Turbomeca S.A. Arriel 2B1 turboshaft engines that do not have modification TU157 incorporated. AD 2007-19-09R1 requires replacement of the hydromechanical metering unit (HMU) with a serviceable HMU. Since we issued AD 2007-19-09R1, we received reports of ruptures on HMU constant delta pressure valves that have less than 2,000 hours in service. This proposed AD would continue to require HMU replacement; reduce the compliance interval; and include the power turbine (C2) cycle consumption rate when determining compliance times. We are proposing this AD to prevent failure of the HMU, which could lead to damage to the engine, and damage to the aircraft.

## Notices in this docket

- Mar 22, 2010: Notice of proposed rulemaking (NPRM). (first notice), FR document 2010-6179, comments due Apr 21, 2010 (https://www.federalregister.gov/documents/2010/03/22/2010-6179/airworthiness-directives-turbomeca-arriel-2b1-turboshaft-engines)
- Dec 24, 2013: Notice of proposed rulemaking (NPRM)., FR document 2013-30488, comments due Feb 24, 2014 (https://www.federalregister.gov/documents/2013/12/24/2013-30488/airworthiness-directives-turbomeca-sa-turboshaft-engines)

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