The Indonesian National Transport Safety Committee has released its findings on the AirAsia Flight QZ8501 crash last December that killed all 162 people on board. Stormy weather had been considered a major factor in the crash. However investigators now say that was not the case.
Instead, the plane's rudder control system malfunctioned four times during the flight, and the pilots’ response to the problem contributed to the disaster.
The soldering on one of the electronic parts in the rudder control system was cracked, causing it to send four warning signals. The pilots reset the computer system, which disabled the autopilot. The co-pilot then lost control of the plane which banked sharply. He then continued to pull the nose of the plane up until it stalled.
The pilot did not appear to take over, and at one point, they seemed to push their joysticks in opposite directions.
Maintenance crews were aware of the problem with the rudder control system, as it had occurred 23 times in the past year, and resetting the system was one of several methods that had been used in the past to address it.
The Airbus A320-200 was travelling from Surabaya to Singapore when crashed into the Java Sea on December 28, 2014.
The report is available here.