An AirAsia X flight took off from Sydney and lost autopilot function after the pilots entered the wrong coordinates before takeoff, forcing the plane to land in an unplanned destination, according to a new report from the Australian Transport Safety Board.
In March of 2015, the pilot of the AirAsia X Airbus A330 incorrectly entered the plane's longitude, making the navigation system believe the plane was near Cape Town, South Africa.
"The magnitude of this error adversely affected the aircraft's navigation functions, global positioning system (GPS) receivers and some electronic centralised aircraft monitoring alerts," the Australian report said.
The pre-flight checks continued normally without the crew noticing the error until after take-off and flying the wrong direction.
What happened next was a series of alerts and potentially dangerous events that caused confusion in the cockpit and on the ground.
First was a "terrain" alert, warning the pilots they were flying too low. The pilots disregarded the warning after a visual check indicated no danger in their path.
The autopilot was engaged at 410 feet and the plane began to turn into the path of other flights expected to take off.
Air traffic controllers warned the pilots of the error and directed the flight towards the ocean so they could attempt to fix the issues while flying over the ocean east of Sydney.
The plane would later lose autopilot and auto-thrust, prompting the decision to return to the airport.
With poor weather rolling into the area, the pilots needed a new airport where they could physically see the runway.
Nearly two hours after its departure from Sydney and a "go-around" on its first landing attempt, the AirAsia flight landed in Melbourne, relying on directions from air traffic control to get there.
The ATSB reported the problem to be caused by the inadvertent longitude input by the captain, followed by "further errors by the flight crew in the diagnosis and actioning of flight deck switches."
Safety investigators also found that the aircraft lacked an upgraded flight management system that would have prevented the initial error.
In a statement provided to ABC News, AirAsia said they have already upgraded the flight management systems in all AirAsia X aircraft, briefed all pilots on "internal investigation findings and reviewing recovery procedures to be undertaken," and developed "a training bulletin and package for flight crew."
The airline has regularly passed safety and security audits by international regulators.