# Proposed AD FAA-2005-21242: Turbomeca Arriel 1B, 1D, 1D1, and 1S1 Turboshaft Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2006-02-08
- Products: Turbomeca
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: March 10, 2010, 75 FR 11072
- Comments due: April 9, 2010
- Became: [AD 2006-02-08](https://openairdocs.org/ad/2006-02-08)
- Docket: FAA-2005-21242 (https://www.regulations.gov/docket/FAA-2005-21242, where comments are filed)
- Project: 2005-NE-09-AD
- FR document: 2010-5028
- Official PDF: https://openairdocs.org/files/sha256/bd/81/bd81d8387852edf3cf77f0620b1868d23619d86da808df2f7411aad558473138 (from https://www.govinfo.gov/content/pkg/FR-2010-03-10/pdf/2010-5028.pdf)
- Federal Register: https://www.federalregister.gov/documents/2010/03/10/2010-5028/airworthiness-directives-turbomeca-arriel-1b-1d-1d1-and-1s1-turboshaft-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1B73C651E66C3561862576E200473D68.0001
- Page: https://openairdocs.org/proposed/FAA-2005-21242

## Summary

The FAA proposes to supersede an existing airworthiness directive (AD) for certain Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines. That AD requires initial and repetitive relative position checks of the gas generator 2nd stage turbine blades on Turbomeca Arriel 1B (that incorporate Turbomeca Modification (mod) TU 148), Arriel 1D, 1D1, and 1S1 turboshaft engines that do not incorporate mod TU 347. That AD also requires initial and repetitive replacements of 2nd stage turbines on Arriel 1B, 1D, and 1D1 engines. This proposed AD would require lowering the repetitive threshold for relative position checks on Arriel 1B engines. This proposed AD would also require lowering the initial and repetitive thresholds for replacement of 2nd stage turbines on Arriel 1B, 1D, and 1D1 engines. This proposed AD results from reports of new cases of failures of 2nd stage turbine blades since we issued AD 2008-07-01. We are proposing this AD to prevent the failure of 2nd stage turbine blades, which could result in an uncommanded in-flight engine shutdown, and a subsequent forced autorotation landing or accident.

## Notices in this docket

- Jun 28, 2005: Notice of proposed rulemaking (NPRM). (first notice), FR document 05-12692, comments due Aug 29, 2005 (https://www.federalregister.gov/documents/2005/06/28/05-12692/airworthiness-directives-turbomeca-arriel-1b-1d-1d1-and-1s1-turboshaft-engines)
- Apr 17, 2006: Notice of proposed rulemaking (NPRM)., FR document E6-5646, comments due Jun 16, 2006 (https://www.federalregister.gov/documents/2006/04/17/E6-5646/airworthiness-directives-turbomeca-arriel-1b-1d-1d1-and-1s1-turboshaft-engines)
- Mar 9, 2007: Notice of proposed rulemaking (NPRM)., FR document E7-4244, comments due May 8, 2007 (https://www.federalregister.gov/documents/2007/03/09/E7-4244/airworthiness-directives-turbomeca-arriel-1b-1d-1d1-and-1s1-turboshaft-engines)
- Mar 10, 2010: Notice of proposed rulemaking (NPRM)., FR document 2010-5028, comments due Apr 9, 2010 (https://www.federalregister.gov/documents/2010/03/10/2010-5028/airworthiness-directives-turbomeca-arriel-1b-1d-1d1-and-1s1-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.