A glitch in the system controlling rudder movement and the pilots' response to the malfunctioning component caused the AirAsia flight QZ8501 to crash in December last year, Indonesian investigators said on Tuesday. The system had recorded problems 23 times in the previous 12 months, they added. The plane crash had killed all 162 people on board.

Investigators said the problem was caused by a cracked soldering joint on an electronic circuit board, reported AP. The flight data recorder showed the rudder control system had sent repeated warnings to the pilots. The plane’s voice recorder indicated possible confusion between the pilot and co-pilot, the investigators said, adding that inclement weather conditions did not lead to the crash as was initially believed.

The pilots had asked to climb from 32,000 feet to 38,000 feet to avoid threatening clouds, but were denied permission because of heavy air traffic. Four minutes later, the plane dropped off the radar without any distress signal. The Airbus A320 aircraft crashed less than halfway into a two-hour flight from Indonesia’s Surabaya city to Singapore. The French aircraft manufacturer declined an immediate comment. "Airbus has just received the final accident report. We are now carefully studying its content," a spokesman told Reuters.