Authorities: Germanwings Tragedy Was No Accident

Only the co-pilot of Germanwings Flight 9525 was in the cockpit when the Airbus A320 slammed into a steep mountainside in the French Alps, a French prosecutor confirmed Thursday, saying he had "intentionally" crashed the aircraft.

French prosecutor Brice Robin said in Marseille on Thursday that the co-pilot, Andreas Lubitz, requested control of the aircraft about 20 minutes into the flight. The pilot then left the cockpit, leaving the co-pilot in full control of the plane.

Lubitz manually and "intentionally" set the plane on the descent that drove it into the mountainside in the southern French Alps. It was the co-pilot's "intention to destroy this plane," Robin said.

The Airbus A320, on a flight from Barcelona to Duesseldorf, began to descend from cruising altitude after losing radio contact with ground control and slammed into the remote mountain on Tuesday morning, killing all 150 people on board.

Robin confirmed a report by The New York Times that the pilot tried aggressively to get back into the cockpit, but was denied access.

The prosecutor said the pilot was heard pleading with the co-pilot over a telephone intercom system from the cabin for access, but that he got no answer from the co-pilot.

Eventually, according to The Times account, "you can hear he (pilot) is trying to smash the door down."

On the cockpit voice recorder, which reached French accident investigators on Wednesday morning, Robin said there is audio of the co-pilot breathing, and that breathing continues until the moment before impact.

"He (co-pilot) was alive until impact," said Robin.

In the German town of Montabaur, acquaintances said Lubitz was in his late twenties and showed no signs of depression when they saw him last fall as he renewed his glider pilot's license.