On March 24, just ten minutes after making routine contact with air traffic control, Germanwings Flight 9525 hit the side of a mountain in the French Alps, killing everyone onboard.

The crash has been labelled as a deliberate act by co-pilot Andreas Lubitz.

Lubitz, 27, locked the doors to the cockpit after the pilot in command excused himself to the restroom.

This was possible because, unlike in the United States, European flight regulations do not require at least two employees in the cockpit at all times.

Pilots do have an emergency code to unlock the door from the outside, but the code panel was manually disabled.

Captain Sondenheimer used the intercom to request re-entry. He knocked and banged on the door demanding to be let back in.

Only steady breathing could be heard on the voice recorder as passengers began to scream.

Lubitz did not transmit a distress call and did not respond to questions from air traffic control.

The autopilot was then set from 38,000 ft to 100 ft. It took only nine seconds for the airplane to begin to descend.

The plane hit the mountain at 430 mph. All 144 passengers and six crew members were killed instantly.

The debris field spread over 500 acres without a single visually identifiable body.

A helicopter landed near the site confirmed that the largest piece of the wreckage appeared to be no larger than a small car, however, investigators were able to isolate 150 sets of DNA to compare to the families of the victims.

German authorities promptly searched property belonging to Lubitz. No suicide note was found, though a doctor’s letter declaring him “unfit to work” was retrieved from the trash can. Germanwings reported no knowledge of the letter.

Police revealed that Lubitz’s internet search history included “ways to commit suicide” and “cockpit doors and their security provisions”.

Lubitz had only 630 hours of flight experience and took several months off from his training after reporting an episode of severe depression. He had been treated for suicidal tendencies before that.

The killer co-pilot grew up with wealthy parents in a stable environment. He had several close friends and a girlfriend. He had no known political or religious motivation.

“He was very polite. He would always say hello and goodbye. There certainly seemed nothing out of the ordinary about him,” said neighbor Johannes Rossbach.

Investigators appear clueless as to why he would have crashed the plane. They have yet to find conclusive evidence linking the crash to Lubitz’s mental health.

Germanwings’ parent company Lufthansa has put aside $300 million to account for all costs relating to the tragedy. Liability to victims could reach over $150,000.

Australian airlines have already reacted to the disaster by mandating that two crew members must be present in the cockpit at all times.

Authorities now predict the largest increase in flight security since 2001.