Indonesia investigators have revealed that a mid-air miscommunication between the pilot and the co-pilot over a technical snag caused AirAsia Flight QZ8501 to plunge into the Java Sea last December.
The Guardian reports that that the AirAsia Airbus A320-200 was en route to Singapore from the Indonesian city of Surabaya on 28 December when it lost contact with air traffic control around 42 minutes after takeoff.
The wreckage of the AirAsia crashed plane and the bodies of the passengers were pulled from the Java Sea later, off Kalimantan, the Indonesian part of Borneo island.
The investigators’ findings reveal the pilot was dealing with a repeated technical problem with the Rudder Travel Limiter (RTL), leaving the co-pilot to take control of the plane. Electrical interruption to the RTL happened three times in the space of 13 minutes, eventually causing the autopilot to disengage.
The co-pilot was left with the option to fly the plane manually with the loss of autopilot and at that point a miscommunication emerged between him and the pilot.
The two black boxes and a cockpit recording reveal that the pilot instructed the co-pilot to ‘pull down’, sending the plane soaring up to 38,000 feet.
Accident investigator Nurcahyo Utomo said the ‘pull down’ order was confusing as when one pull’s down [the gear controls] the plane goes up. But to make the plane go down one needs to push.
The report added that at one point, both the pilots appeared to be pushing the controls in the ‘opposite’ directions as the plane went into a ‘prolonged stall condition that was beyond the capability of the crew to recover’.
The AirAsia crash report by Indonesia’s National Transportation Safety Commission where they have presented findings from an almost year-long investigation, are the official explanation of what caused the aircraft to crash.