Lufthansa flight incident reports have revealed a previously undisclosed emergency that occurred on board a passenger flight from Frankfurt to Seville in February 2023, the BILD reports. The incident involved a rare and dangerous moment when an Airbus A321 was temporarily left without conscious human control in the cockpit at cruising altitude.

According to findings recently released by Spain’s air accident investigation agency, the flight was cruising at 10,700 meters (35,000 feet) when the captain left the cockpit to use the restroom. Just after he exited, the co-pilot suddenly lost consciousness, reportedly due to an undiagnosed medical condition.

While the aircraft’s autopilot system took over, the situation became critical because the cockpit door remained locked. Modern cockpit security protocols require internal confirmation to reopen the door—something the unconscious co-pilot could not provide. As a result, the captain was locked out of the cockpit for several minutes, unable to intervene as the aircraft slightly veered off course.

Fortunately, after about eight minutes, the co-pilot regained consciousness and unlocked the door, allowing the captain to re-enter and take control. The flight crew quickly made the decision to divert the flight and perform an emergency landing in Madrid, where medical personnel met the aircraft upon arrival.

The co-pilot was immediately taken for medical evaluation, where doctors later determined that the cause of the collapse was a previously unknown neurological disorder. No injuries to passengers or crew were reported, and the flight was safely completed under emergency protocols.

The incident, which took place on 17 February 2023, was kept out of the public eye until now. It has sparked new conversations about pilot health checks, emergency procedures, and cockpit access protocols during single-pilot operations, even under short-term circumstances.