What happened
On 25 June 2026, at approximately 09:30 local time, a Diamond DA40 with registration SP-RDW was in flight shortly after departing from EPZE. While transiting the control zone of EPKS, roughly four nautical miles south of the aerodrome over a forest complex, an "OPEN DOORS" warning appeared in the cockpit.
The pilot observed that the rear cabin door had partially unlocked. An attempt to secure and close the door resulted in further movement of the panel. Shortly thereafter, the door completely separated from the aircraft during flight, taking its hinges with it. The pilot immediately decided to return to the departure aerodrome and executed a precautionary landing without delay. The approach and landing were safe, and no injuries were reported among the crew or passengers.
The investigation
The Polish State Commission for Aviation Accident Investigation (PKBWL) reviewed the final report prepared by the investigating entity. The commission assessed the findings as sufficient to conclude the investigation under applicable aviation laws. The inquiry focused on the sequence of events leading to the door separation and the pilot's response.
Findings
The specific cause of the spontaneous unlocking of the rear cabin door could not be established. No contributing factors were identified in the analysis. The commission accepted preventive measures proposed by the investigating party, noting that during type training for the DA40 (and potentially similar models such as the DA42, DA62, and DA50), pilots should be specifically instructed not to attempt to re-close doors in flight. These doors are secured against accidental detachment by a safety hook; attempting to close them may release this mechanism.
Safety action
The commission accepted the recommendation that type training curricula emphasize the danger of manipulating cabin doors during flight, highlighting that the safety hooks designed to prevent detachment can be inadvertently released if pilots attempt to secure partially open doors.