The Germanwings flight GWI18G took off from El Prat airport near Barcelona, Spain, 26 minutes late at 10.01 am on the 24th of March 2015. Approximately an hour into the flight towards Dusseldorf, Germany, it began a slow descent from a 36000-foot cruising altitude until it crashed into a mountainside in an isolated region north of Nice in France. The air traffic controllers had been unable to contact the flight from when it began its unauthorized descent and lost contact with it on impact. All aboard were killed. As soon as the black box was recovered the investigation very quickly focused on the copilot Andreas Lutz: his patchy psychological history and especially a letter from his doctor giving him work leave to cure his “suicidal tendencies” alerted the authorities to what might have gone wrong.