# Proposed AD FAA-2023-1991: CFM International, S.A. Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2024-07-06
- Products: CFM International
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: October 11, 2023, 88 FR 70409
- Comments due: November 27, 2023
- Became: [AD 2024-07-06](https://openairdocs.org/ad/2024-07-06)
- Docket: FAA-2023-1991 (https://www.regulations.gov/docket/FAA-2023-1991, where comments are filed)
- Project: AD-2023-00700-E
- FR document: 2023-22373
- Official PDF: https://openairdocs.org/files/sha256/87/b2/87b2a45b0443b33fa7c666f4370ca6ca5f47694a9e2eefbedd5df3f010368ceb (from https://www.govinfo.gov/content/pkg/FR-2023-10-11/pdf/2023-22373.pdf)
- Federal Register: https://www.federalregister.gov/documents/2023/10/11/2023-22373/airworthiness-directives-cfm-international-sa-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FR-ADNPRM-2023-22373-00000000000.0001
- Page: https://openairdocs.org/proposed/FAA-2023-1991

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model LEAP-1A23, LEAP-1A24, LEAP-1A24E1, LEAP-1A26, LEAP-1A26CJ, LEAP-1A26E1, LEAP-1A29, LEAP- 1A29CJ, LEAP-1A30, LEAP-1A32, LEAP-1A33, LEAP-1A33B2, and LEAP-1A35A engines. This proposed AD was prompted by a report of multiple aborted takeoffs and air turn-backs (ATBs) caused by high-pressure compressor (HPC) stall, which was induced by high levels of non-synchronous vibration (NSV). Additional manufacturer investigation revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV. This proposed AD would require initial and repetitive calculations of the levels of NSV, inspection of the stage 2 high- pressure turbine (HPT) nozzle assembly honeycomb and HPT stator stationary seal honeycomb and, depending on the results of the calculations and inspections, replacement of certain parts. This proposed AD would also require replacement of the No. 3 bearing spring finger housing. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Oct 11, 2023: Notice of proposed rulemaking (NPRM). (first notice), FR document 2023-22373, comments due Nov 27, 2023 (https://www.federalregister.gov/documents/2023/10/11/2023-22373/airworthiness-directives-cfm-international-sa-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.