The AirAsia plane that plunged into the Java Sea last month was being flown by the French co-pilot and not the captain as it climbed sharply and then crashed according to Indonesian investigators who say black box data has given a ‘pretty clear picture’ of what happened.

The cause of the accident however is still unknown.

The Airbus A320 vanished from radar screens in bad weather en route from Indonesia’s second-biggest city of Surabaya to Singapore. All 162 people on board were killed.

“The second-in-command, popularly known as the co-pilot, who usually sits to the right of the cockpit. At the time, he was flying the plane,” said head National Transport Safety Committee (NTSC) investigator Mardjono Siswosuwarno, referring to first officer Remi Plesel.

“The captain, sitting to the left, was the pilot monitoring.”

Investigators said the cockpit voice and flight data recorders showed that the plane had been cruising at a stable altitude before the accident. The aircraft was in