Germanwings Flight 9525 is something you should Google when you have 20 minutes of free time. The story is absolutely insane - and tragic. And terrifying.
This was a deliberate crash that happened in March of 2015. All 144 passengers and 6 crew members were killed when the plane crashed. The Co-pilot Andreas Lubitz was depressed and suicidal. A doctor had declared him unfit for work, which he kept from Germanwings. He took control of the plane and crashed it.
It was a controlled descent that ultimately drove the plane into a mountain. The pilot got up to go to the bathroom and when he came back to the cockpit, the door was locked.
Now the pilot has a code to unlock the cockpit door but Andreas simply disabled the code pad from inside the cockpit. The pilot tried to break down the door too, but cockpit doors -