# Proposed AD FAA-2019-0597: CFM International, S.A. Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2021-16-08
- Products: CFM International
- Product type: Engine
- Action: Supplemental notice of proposed rulemaking (SNPRM).
- Published: March 23, 2021, 86 FR 15436
- Comments due: May 7, 2021
- Became: [AD 2021-16-08](https://openairdocs.org/ad/2021-16-08)
- Docket: FAA-2019-0597 (https://www.regulations.gov/docket/FAA-2019-0597, where comments are filed)
- Project: 2019-NE-05-AD
- FR document: 2021-05600
- Official PDF: https://openairdocs.org/files/sha256/74/1a/741af3cb7302010bbb647ab4f226c65788948ed35e09a665c2882fb670a63d96 (from https://www.govinfo.gov/content/pkg/FR-2021-03-23/pdf/2021-05600.pdf)
- Federal Register: https://www.federalregister.gov/documents/2021/03/23/2021-05600/airworthiness-directives-cfm-international-sa-turbofan-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/3E59AB652F049ED5862586A10057A240.0001
- Page: https://openairdocs.org/proposed/FAA-2019-0597

## Summary

The FAA is revising a notice of proposed rulemaking (NPRM) that applied to certain CFM International, S.A. (CFM) CFM56-5B, CFM56- 5C, and CFM56-7B model turbofan engines with a certain rotating air high-pressure turbine (HPT) front seal. This action revises the NPRM by requiring CFM56-5B or CFM56-7B model turbofan engines with an installed reconfigured rotating air HPT front seal, which was previously installed and operated in a CFM56-5C model turbofan engine, to follow the removal requirements for the CFM56-5C model turbofan engine. The FAA is proposing this airworthiness directive (AD) to address the unsafe condition on these products. Since these actions would impose an additional burden over those in the NPRM the agency is requesting comments on this SNPRM.

## Notices in this docket

- Oct 23, 2019: Notice of proposed rulemaking (NPRM). (first notice), FR document 2019-23089, comments due Dec 9, 2019 (https://www.federalregister.gov/documents/2019/10/23/2019-23089/airworthiness-directives-cfm-international-sa-turbofan-engines)
- Mar 23, 2021: Supplemental notice of proposed rulemaking (SNPRM)., FR document 2021-05600, comments due May 7, 2021 (https://www.federalregister.gov/documents/2021/03/23/2021-05600/airworthiness-directives-cfm-international-sa-turbofan-engines)

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