WATCH: How to Lock & Unlock an Airbus A320 Cockpit Door

According to French prosecutor Brice Robin, Germanwings pilot Andrea Lubitz deliberately locked Captain Patrick Sonderheimer out of the cockpit of their plane. Then, Lubitz deliberately crashed the aircraft into the French Alps, killing all 150 on board.

The plane’s blackbox recorder shows that Sonderheimer couldn’t get back in the cockpit after going to the bathroom. Above you can see what Lubitz would have to have done to keep Sonderheimer out of the cockpit. Even after the captain entered the seven-digit code to open the door, it doesn’t open for five minutes as part of its programing.

Harrowing.