# Proposed AD 97-ANE-29-AD: CFM International CFM56-5B/2P Series Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 98-02-04
- Action: Notice of proposed rulemaking (NPRM).
- Published: September 19, 1997, 62 FR 49179
- Comments due: November 18, 1997
- Became: [AD 98-02-04](https://openairdocs.org/ad/98-02-04)
- Docket: 97-ANE-29-AD
- FR document: 97-24911
- Official PDF: https://openairdocs.org/files/sha256/b6/11/b61180a447604e575e249b7ad37be4eb6b91af22afc96b7240ae91a3c95a8994 (from https://www.govinfo.gov/content/pkg/FR-1997-09-19/pdf/97-24911.pdf)
- Federal Register: https://www.federalregister.gov/documents/1997/09/19/97-24911/airworthiness-directives-cfm-international-cfm56-5b2p-series-turbofan-engines
- Page: https://openairdocs.org/proposed/97-ANE-29-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to CFM International (CFMI) CFM56-5B/ 2P series turbofan engines. This proposal would require a reduction of the low cycle fatigue (LCF) retirement life for certain low pressure turbine (LPT) cases. This proposal is prompted by the results of a refined life analysis performed by the manufacturer which revealed minimum calculated LCF lives significantly lower than the published LCF retirement life. The actions specified by the proposed AD are intended to prevent a LCF failure of the LPT case, which could result in damage to the aircraft.

## Notices in this docket

- Sep 19, 1997: Notice of proposed rulemaking (NPRM). (first notice), FR document 97-24911, comments due Nov 18, 1997 (https://www.federalregister.gov/documents/1997/09/19/97-24911/airworthiness-directives-cfm-international-cfm56-5b2p-series-turbofan-engines)

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