# Proposed AD FAA-2025-1365: Lycoming Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2026-04-11
- Products: Lycoming Engines
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: August 7, 2025, 90 FR 38081
- Comments due: September 22, 2025
- Became: [AD 2026-04-11](https://openairdocs.org/ad/2026-04-11)
- Docket: FAA-2025-1365 (https://www.regulations.gov/docket/FAA-2025-1365, where comments are filed)
- Project: AD-2024-00684-E
- FR document: 2025-15039
- Official PDF: https://openairdocs.org/files/sha256/a7/51/a751480f1911c0de44d9b09f82f0d2a866d0347ec9e2ecdb32b8b1612e38a858 (from https://www.govinfo.gov/content/pkg/FR-2025-08-07/pdf/2025-15039.pdf)
- Federal Register: https://www.federalregister.gov/documents/2025/08/07/2025-15039/airworthiness-directives-lycoming-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FR-ADNPRM-2025-15039-00000000000.0001
- Page: https://openairdocs.org/proposed/FAA-2025-1365

## Summary

The FAA proposes to supersede Airworthiness Directive (AD) 2024-21-02, which applies to Lycoming Engines (Lycoming) model engines that have certain connecting rod assemblies installed. AD 2024-21-02 requires repetitive oil inspections for bronze metal particulates and, if found, additional inspections of the connecting rod bushings for damage, proper fit, movement, and wear, and replacement if necessary. As terminating action to the connecting rod bushing inspections, AD 2024-21-02 also requires replacement of the connecting rod bushings with parts eligible for installation. Since the FAA issued AD 2024-21- 02, the ship date range for potentially affected parts that may be subject to connecting rod failure has been expanded, and additional parts that are eligible for installation have been identified. This proposed AD would require the actions in AD 2024-21-02 and would require expanding the applicability. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Aug 7, 2025: Notice of proposed rulemaking (NPRM). (first notice), FR document 2025-15039, comments due Sep 22, 2025 (https://www.federalregister.gov/documents/2025/08/07/2025-15039/airworthiness-directives-lycoming-engines)

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