While locked out of the cockpit, the captain of flight 9525 tried to break the door but failed, as the plane crashed into the mountain.

Andreas Lubitz participates in a running race in Hamburg, northern Germany on September 13, 2009. Photo: AP.

The final moments on board a Germanwings plane, before it crashed into the French Alps, sound like something out of a horror movie.

“Andreas, open the door, open the door,” the captain shouted as he tried to break open the cockpit door with an axe, The Epoch Times reported.

According to prosecutors who listened to the cockpit voice recorder, passengers burst into tears in terror as they realized the plane was about to crash. Investigators also heard loud banging on the door while co-pilot Andreas Lubitz said nothing. They could only hear the pilot breathing.

A French military official gave more details about the final moments.

"The man outside knocked lightly on the door but there was no response. Then he banged on the door harder and there was no response. There was never an answer. You could hear the captain trying to break the door down," he said.

German newspaper Bild, citing security sources, reported that Captain Patrick Sonderheimer had tried to break through the cockpit's armoured door with an axe. The information could not be directly verified, but a spokesman for German airline Germanwings confirmed to AFP that an axe was on board. The airline said such an axe was "part of the safety equipment of an Airbus A320".

Co-pilot Lubitz was due to marry next year but recently split from his fiancee. The 28-year-old pilot is said to be going through a “personal crisis” after the relationship collapsed. The theory was put forward hours after The Guardian reported that Lubitz had to suspend his pilot training six years ago due to “psychological problems”.

Authorities have confirmed that the co-pilot hid his illness from his employer. Investigators found several doctor's notes at his home saying Lubitz was unfit to work. The notes "support the preliminary assessment that he concealed his illness from his employer and colleagues." Investigators did not find a suicide note or "any religious or political statements" that could be linked to the crash.

“The documents found contained medical information about the diagnosis and the corresponding treatment by doctors,” Ralf Herrenbrück, a spokesman for prosecutors in the city of Düsseldorf, told The New York Times.

In the eyes of Lubitz's neighbors, the co-pilot was a physically fit person.

"He didn't smoke and really looked after himself. He was a jogger and very fit," said Johannes Rossmann, who lives near the Germanwings pilot's home in the town of Montabaur.

People in the town who knew Lubitz said the pilot loved his job at Germanwings and seemed very happy.

In the United States, the Federal Aviation Administration requires a crew member to remain in the cockpit when one of the pilots leaves, but there is no such requirement in Europe. However, that rule may soon be reconsidered, with several airlines including Air Canada, Norwegian Air Shuttle, and easyJet saying on March 26 that they would require two crew members to remain in the cockpit at all times.

According to Vnexpress