What happened
On February 26, 2025, a Cessna 310Q, registered as LV-JZD, departed from San Carlos de Bariloche International Airport (SAZS) at 16:15 UTC, bound for Puerto Deseado (SAWD). During the cruise phase of the flight, while maintaining an altitude of 8,000 feet and approximately 24 nautical miles from the departure airport, the crew noticed that the cabin door had partially opened by about 2 centimeters.
The crew identified that the door handle was not properly locked. Despite the crew's efforts to close and secure the door while in flight, the opening increased. Due to the instability of the door, the pilot declared an emergency and initiated a return to the origin airport. The remainder of the flight proceeded without further complications.
The investigation
This was a desk investigation conducted by the JST. Upon landing at Bariloche, the pilot performed a visual inspection of the aircraft but found no apparent damage to the door's locking mechanism. To facilitate the aircraft's return to service, maintenance personnel conducted a formal inspection and verified the door locking system in accordance with the manufacturer's service manual.