# Proposed AD FAA-2006-23704: Honeywell International Inc. TPE331 Series Turboprop, and TSE331-3U Model Turboshaft Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2006-14-03
- Products: Honeywell International
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: February 23, 2006, 71 FR 9281
- Comments due: April 24, 2006
- Became: [AD 2006-14-03](https://openairdocs.org/ad/2006-14-03)
- Docket: FAA-2006-23704 (https://www.regulations.gov/docket/FAA-2006-23704, where comments are filed)
- Project: 2006-NE-02-AD
- FR document: E6-2574
- Official PDF: https://openairdocs.org/files/sha256/7b/3c/7b3c4bc2c878a4583953b273782ae340af3021a33f109ad4d3713785ac027dc6 (from https://www.govinfo.gov/content/pkg/FR-2006-02-23/pdf/E6-2574.pdf)
- Federal Register: https://www.federalregister.gov/documents/2006/02/23/E6-2574/airworthiness-directives-honeywell-international-inc-tpe331-series-turboprop-and-tse331-3u-model
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/EAAF57BC7D8CEC7A8625711E006BD8E0.0001
- Page: https://openairdocs.org/proposed/FAA-2006-23704

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain Honeywell International Inc. TPE331 series turboprop, and TSE331-3U model turboshaft engines. This proposed AD would require implementing a new flight cycle counting method for first, second, and third-stage turbine rotors used in aircraft that make multiple takeoffs and landings without an engine shutdown, and removing turbine rotors from service that have reached or exceeded their cycle life limits. This new flight cycle counting method would require determining total equivalent cycles accrued. This proposed AD results from several reports of uncontained turbine rotor separation on engines used in special-use operations. We are proposing this AD to prevent uncontained failure of the turbine rotor due to low-cycle-fatigue (LCF), and damage to the aircraft.

## Notices in this docket

- Feb 23, 2006: Notice of proposed rulemaking (NPRM). (first notice), FR document E6-2574, comments due Apr 24, 2006 (https://www.federalregister.gov/documents/2006/02/23/E6-2574/airworthiness-directives-honeywell-international-inc-tpe331-series-turboprop-and-tse331-3u-model)

---
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.