Pilot error is the reason an Air Asia X flight took passengers to Melbourne, instead of its intended destination Kuala Lumpur.
The Australian Transport Safety Bureau has released its findings into the flight which departed Sydney in March 2015.
It says when the flight took off from one runway, air traffic control observed it was in the flight path of a parallel runway at the airport. This sparked concerns around the accuracy of the on-board navigation systems.
It wasn't until the plane was airborne that the pilot had entered the wrong longitudinal position which led the plane to fly in the wrong direction.
The flight crew tried frantically to correct the problem but only managed to make things worse, also affecting the aircraft's flight guidance and flight control systems.
At this point the plane should have returned to Sydney but bad weather, combined with the damaged systems, meant the plane could only land with a clear view of the runway - something it didn't have.
The plane was then diverted to Melbourne where it could land in "visual conditions."
The Safety Bureau also found the aircraft was not fitted with an upgraded flight management system which would have prevented the pilot's data entry error.
In a statement, Air Asia X said it has since upgraded all of their aircraft to new flight management systems as well as creating a training program for flight crew to emphasise the importance of entering the correct data.