FAA Orders Door Inspections for Nearly 1,000 Diamond DA40 Aircraft
The Federal Aviation Administration (FAA) has issued a new Airworthiness Directive (AD) for all Diamond DA40, DA40 F, and DA40 NG aircraft following reports of passenger doors separating during flight. The rule takes effect December 7, 2026, and affects an estimated 987 U.S.-registered airplanes.
The directive requires operators to:
- Revise their Airplane Flight Manuals (AFMs) with updated operating limitations and emergency procedures.
- Perform recurring inspections of the passenger door latching mechanism and safety hook system.
- Complete corrective actions if faults are found, potentially including replacement of the gas spring, hook assembly, retaining block, or door guide blocks.
Diamond Aircraft Industries attributed some incidents to improperly latched doors and pilots attempting to secure them after takeoff. The FAA rejected requests to exclude the newer DA40 NG model, noting that its secondary safety latch does not fully resolve the unsafe condition.
This is not the first time the DA40 door design has drawn regulatory attention. Similar concerns prompted FAA action in 2010, following 31 reported door separation events.
The FAA estimates the initial inspection will cost approximately $331 per aircraft, plus $85 for flight manual revisions. Flight schools and other high-utilization operators are expected to face the greatest impact.
The agency describes the directive as an interim measure. Additional rulemaking may follow as Diamond continues investigating the root cause.
Source: AVweb – FAA Orders DA40 Door Inspections After In-Flight Separations