French Officials Say Germanwings Co-Pilot Practiced Dangerous Descents Before Crash

Officials investigating the intentional crash of Germanwings Flight 9525 have found that the plane's pilot had previously practiced a dangerous descent on another passenger plane ahead of the March crash that killed all 150 on board.

French investigators say that Andreas Lubitz had practiced plunging a passenger-filled Airbus A320 as low as 100 feet from the ground and then quickly bringing the plane back up to normal altitude before it was detected.

Lubitz had reportedly practiced the rapid decent and autopilot options of the plane while he was alone in the cockpit for less than five minutes.

The German pilot is accused of flying Germanwings Flight 9525 into the French Alps on March 24, killing all 150 passengers on board as the plane traveled from Barcelona to Dusseldorf.

Lubitz has also been accused of researching suicide on the internet and searching for information on the mechanisms behind cockpit doors.

Aviation experts have offered their opinion on Lubitz's mindset when he plotted his mass murder and suicide.

Aviation expert Alastair Rosenschein, who previously worked with British Airways, told NBC News that he thinks Lubitz's previous experiments with rapid descent were in reality aborted suicide attempts.

"My perspective on this is that he was actually thinking of committing suicide on the way out on the outbound flight but changed his mind," Rosenschein told the media outlet.

"There is no need for the pilot to practice doing this sort of thing because he knows the equipment fully. It's not a question of 'if I turn this knob will this happen?' He already knows all that, he's a qualified airline pilot so I think it was just that he bottled out of committing suicide on the outbound flight."