# Proposed AD FAA-2007-0157: Turbomeca Makila 1 A and 1 A1 Turboshaft Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2008-08-16
- Products: Turbomeca
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: November 15, 2007, 72 FR 64172
- Comments due: January 14, 2008
- Became: [AD 2008-08-16](https://openairdocs.org/ad/2008-08-16)
- Docket: FAA-2007-0157 (https://www.regulations.gov/docket/FAA-2007-0157, where comments are filed)
- Project: 2001-NE-23-AD
- FR document: E7-22330
- Official PDF: https://openairdocs.org/files/sha256/77/70/7770a139ad8367d7443223a0533bd47a6e76eb15560d28c538240def57d7c2ec (from https://www.govinfo.gov/content/pkg/FR-2007-11-15/pdf/E7-22330.pdf)
- Federal Register: https://www.federalregister.gov/documents/2007/11/15/E7-22330/airworthiness-directives-turbomeca-makila-1-a-and-1-a1-turboshaft-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D710F7DD06C5DA46862573940058BEE7.0001
- Page: https://openairdocs.org/proposed/FAA-2007-0157

## Summary

The FAA proposes to supersede an existing airworthiness directive (AD) for Turbomeca Makila 1 A, 1 A1, and 1 A2 turboshaft engines. That AD currently requires replacing certain digital electronic control units (DECUs) and electronic control units (ECUs) with modified DECUs and ECUs. This proposed AD would apply only to Makila 1 A and 1 A1 turboshaft engines, and would require replacing the selector-comparator board in the ECU with a board incorporating Turbomeca modification TU 250. This proposed AD results from recent unexplained reversions of the ECU to the 65% N1 back-up mode. We are proposing this AD to prevent dual-engine reversion of the ECU to the 65% N1 back-up mode, which could lead to inability to continue safe flight, emergency autorotation landing, or an accident.

## Notices in this docket

- Nov 15, 2007: Notice of proposed rulemaking (NPRM). (first notice), FR document E7-22330, comments due Jan 14, 2008 (https://www.federalregister.gov/documents/2007/11/15/E7-22330/airworthiness-directives-turbomeca-makila-1-a-and-1-a1-turboshaft-engines)

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