Indonesia’s National Transportation Safety Committee released a final report, detailing the events that led to the AirAsia Airbus A320 crash last December that killed all 162 people on board.
Bad weather did not play a role in the crash, as initially speculated; instead, system malfunction and the crew’s response were the contributing factors. The initial faults appear to stem from a rudder control system malfunction, which had occurred 23 times in the year prior the crash.
A cracked solder joint on an electric card caused the rudder system to malfunction four times on the Dec. 28, 2014 flight. While the rudder malfunction itself likely would not have led to a crash, a crew member appears to have removed a circuit breaker in an attempt to reset the system — outside of handbook recommendations — causing the autopilot to disengage. After this, the aircraft began to roll, but reports show that no movement was detected on the manual stick for nine seconds.
The accident report states that this changed the flight control logic from “normal law to alternate law, the rudder deflecting 2 degrees to the left.”
The voice recorder shows an apparent miscommunication between the pilot and copilot. The pilot says, “pull down,” but the plane is rapidly ascending at a 54-degree angle of bank, before entering a prolonged stall and plummeting into the Java Sea.
Chief executive of AirAsia, Tony Fernandes, tweeted, “There is much to be learned here for AirAsia, the manufacturer and the aviation industry. We will not leave any stone unturned to make sure the industry learns from this tragic incident.”