Germanwings crash: Co-pilot tested descents hours before crash

Authorities are still puzzling over why Andreas Lubitz sent Flight 9525 from Barcelona to Duesseldorf straight into a mountain, killing all 150 people on board

A co-pilot who purposely crashed a Germanwings A320 plane into the French Alps appeared to have rehearsed sending the jet into a deadly descent on another flight just two hours earlier, investigators said today.

Authorities are still puzzling over why Andreas Lubitz, who had suffered from suicidal tendencies and depression in the past, locked the captain out of the cockpit on March 24 and sent Flight 9525 from Barcelona to Duesseldorf straight into a mountain, killing all 150 people on board.

The revelation about the earlier flight that day from Duesseldorf to Barcelona appeared to support the theory that the Germanwings crash was not only deliberate but premeditated. It came in a 30-page interim report from the French accident investigation agency BEA.

The development also raised questions about all flights where Lubitz was in the cockpit but BEA told The Associated Press that, due to practical considerations, it would not investigate those flights.

Lubitz seemed to be toying with the airplane's settings on the flight into Barcelona, programming it for a sharp descent multiple times in a 4 1/2-minute period while the pilot was out of the cockpit before resetting the controls, the report said. Unlike the later flight, he did not lock the pilot out of the cockpit.

On the flight to Barcelona, the plane's "selected altitude" changed repeatedly and several times was set as low as 100 feet (30 meters) above sea level. The report says Lubitz also put the engines on idle, which gives the plane the ability to quickly descend.

On the return flight to Germany, Lubitz also set a 100-foot altitude before the plane crashed into the Alps. Aviation experts say it would be highly unusual for a pilot to repeatedly set a plane for such a low altitude for no apparent reason. But the report said Lubitz did so while air traffic controllers were asking him to bring the airplane down gradually from 35,000 feet to 21,000 feet for its descent to Barcelona.