After an inquiry into the accident, it was determined that co-pilot Andreas Lubitz intentionally caused the crash by locking the pilot out of the cockpit and overriding a system that would have allowed the crew to enter the flight deck in an emergency.

About an hour after the plane’s departure from Barcelona at around 10 AM, first officer Captain Patrick Sondenheimer stepped out of the cockpit to use the lavatory.

Lubitz changed the chosen altitude from 38,000 feet to 100 feet and started a quick drop into the mountains below once Sondenheimer left, locking the door.

Using the aircraft’s black box recorder, an inquiry into the tragedy was able to piece together the last moments of the tragic trip. The plane’s last connection with air traffic control occurred approximately 30 minutes