A jetliner struggled to liftoff and only took flight after slamming its tail into the runway in March because someone entered the wrong weight for the plane into the flight's computer, Australian investigators said Thursday.
As the Airbus 340, carrying 275 people, reached takeoff speed, the Emirates airline captain called for his co-pilot to begin liftoff, but the plane's nose did not rise off the ground, the Transport Safety Bureau said.
With the end of the runway approaching, the captain again called for liftoff, and the co-pilot tried again — this time raising the nose but leaving the tail dragging on the ground.
The captain then pushed the thrust levers to the maximum setting, the engines roared and the plane finally took off.
No one was hurt in the March 20 incident at Melbourne airport in southern Australia.
The tail ripped out at least one runway light and a radio antenna, and a flight data recorder at the rear of the plane was dislodged.
Passengers in the rear of the plane may have seen a shower of sparks from the grinding tail, and many on board would have felt bumping, said Julian Walsh, the Transport Safety Bureau's director of aviation safety investigation.
The plane dumped its fuel at sea and returned to Melbourne for an emergency landing.
The bureau said in a preliminary report that the weight of the plane entered into a computer used to calculate how much thrust was needed for a safe takeoff was too light by 112 tons (100 metric tons).
Walsh signaled that human error was believed to be the cause.
"There's no suggestion of any problem with the aircraft," he told reporters in the national capital, Canberra. "The focus of the investigation is on the operation of the aircraft."
Dubai-based Emirates said in a statement that an internal investigation was under way into how the wrong data was punched into the computer.