# Proposed AD FAA-2026-4633: Diamond Aircraft Industries Inc. Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Comment period closed
- Products: Diamond Aircraft Industries
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: May 13, 2026, 91 FR 26952
- Comments due: June 29, 2026
- Docket: FAA-2026-4633 (https://www.regulations.gov/docket/FAA-2026-4633, where comments are filed)
- Project: MCAI-2025-01173-A
- FR document: 2026-09574
- Official PDF: https://openairdocs.org/files/sha256/b4/db/b4db1e9800b6944994c6fceec222571e3602c4da8e3189425bb97b66dd35b1a1 (from https://www.govinfo.gov/content/pkg/FR-2026-05-13/pdf/2026-09574.pdf)
- Federal Register: https://www.federalregister.gov/documents/2026/05/13/2026-09574/airworthiness-directives-diamond-aircraft-industries-inc-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FR-ADNPRM-2026-09574-00000000000.0001
- Page: https://openairdocs.org/proposed/FAA-2026-4633

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for all Diamond Aircraft Industries Inc. (DAI) Model DA 40, DA 40 F, and DA 40 NG airplanes. This proposed AD was prompted by several reports of passenger door separation during flight. This proposed AD would require revising the existing airplane flight manual (AFM) to provide the flight crew with revised operating limitations, emergency procedures, and normal operating procedures; inspecting the passenger door latching mechanism and safety hook mechanism areas and performing corrective action, as applicable; inspecting the safety hook, latching bolts, front and rear door guide blocks, canopy and passenger door warning light, carbon hinges, tension spring, retaining block, safety hook push button, latching mechanism spring, gas spring, and door frame; measuring the passenger door handle actuation force; modifying the airplane with placards; replacing the gas spring; and replacing the hook assembly, retaining block, door guide blocks, and door sealant if necessary. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- May 13, 2026: Notice of proposed rulemaking (NPRM). (first notice), FR document 2026-09574, comments due Jun 29, 2026 (https://www.federalregister.gov/documents/2026/05/13/2026-09574/airworthiness-directives-diamond-aircraft-industries-inc-airplanes)

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