# Proposed AD FAA-2025-5397: Diamond Aircraft Industries Inc. Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2026-06-03
- Products: Diamond Aircraft Industries
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: December 23, 2025, 90 FR 60031
- Comments due: February 6, 2026
- Became: [AD 2026-06-03](https://openairdocs.org/ad/2026-06-03)
- Docket: FAA-2025-5397 (https://www.regulations.gov/docket/FAA-2025-5397, where comments are filed)
- Project: MCAI-2025-00972-A
- FR document: 2025-23794
- Official PDF: https://openairdocs.org/files/sha256/15/7d/157da8380f92e1c3aa504ba2c54c898eddec0769d4d2cd132c36fa5b7e6f6edc (from https://www.govinfo.gov/content/pkg/FR-2025-12-23/pdf/2025-23794.pdf)
- Federal Register: https://www.federalregister.gov/documents/2025/12/23/2025-23794/airworthiness-directives-diamond-aircraft-industries-inc-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FR-ADNPRM-2025-23794-00000000000.0001
- Page: https://openairdocs.org/proposed/FAA-2025-5397

## Summary

The FAA proposes to supersede Airworthiness Directive (AD) 2020-14-06, which applies to all Diamond Aircraft Industries Inc. (DAI) Model DA 40, DA 40 F, and DA 40 NG airplanes. AD 2020-14-06 requires replacing affected parts, inspecting the fuel tank chambers, and removing rubber material that has detached from the fuel tank connection hoses. AD 2020-14-06 also prohibits installing an affected part on any airplane. Since the FAA issued AD 2020-14-06, additional affected parts installed during production on Model DA 40 NG airplanes have been reported. As a result, the manufacturer has published updated service material for the Model DA 40 NG. This proposed AD would require the same actions as AD 2020-14-06 and would require updated service material to be used for the Model DA 40 NG airplanes. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Dec 23, 2025: Notice of proposed rulemaking (NPRM). (first notice), FR document 2025-23794, comments due Feb 6, 2026 (https://www.federalregister.gov/documents/2025/12/23/2025-23794/airworthiness-directives-diamond-aircraft-industries-inc-airplanes)

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