2026-22310·DEPARTMENT OF TRANSPORTATION

Airworthiness Directives; Diamond Aircraft Industries Inc. Airplanes

Final RuleFinal Rule

Published: Nov 2, 2026
Effective: Dec 7, 2026
Citation: 91 FR 68873
Docket: Docket No. FAA-2026-4633, Project Identifier MCAI-2025-01173-A, Amendment 39-23508
Agencies: DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration

Final rule.

Summary

The Federal Aviation Administration (FAA) has issued a new airworthiness directive (AD) that requires owners of Diamond Aircraft Industries Inc. Model DA 40, DA 40 F, and DA 40 NG airplanes to change the aircraft’s flight manual and carry out a series of inspections, repairs, and part replacements. The action was triggered by multiple incidents in which the passenger door detached while the plane was in the air. By updating operating limits, emergency procedures, and normal flight instructions, and by checking and, if needed, fixing the door‑latching system, safety hook, hinges, springs, guide blocks, sealant and related components, the FAA aims to eliminate the risk of door loss‑of‑containment. The rule is a final rule issued by the FAA, the aviation safety arm of the U.S. Department of Transportation. It applies to every DA 40‑series airplane currently registered in the United States, as well as to the pilots, maintenance providers, and operators who are responsible for keeping those aircraft airworthy. The AD became effective on December 7, 2026, after its publication in the Federal Register on November 2, 2026 (91 FR 68873). Because it is a final rule, there is no additional public comment period. Affected owners must revise the airplane flight manual and complete the required inspections, part replacements and placarding within the compliance time frames specified in the AD—typically a matter of weeks to a few months after the effective date. Compliance will be documented and inspected during routine FAA oversight to ensure the safety issue is fully resolved.

AI-generated summary — verify against the Federal Register text.

Official abstract

The FAA is adopting a new airworthiness directive (AD) for all Diamond Aircraft Industries Inc. (DAI) Model DA 40, DA 40 F, and DA 40 NG airplanes. This AD was prompted by several reports of passenger door separation during flight. This AD requires 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 issuing this AD to address the unsafe condition on these products.