30 April 2009

Emirates near-miss probe identifies data entry error

CANBERRA - An error in the cockpit has been identified by a preliminary report into an incident that saw an Emirates Airbus A340-500 passenger jet suffer substantial damage on March 20 after its tail clipped the runway during take-off from Melbourne Airport

The jet with 257 passengers and 18 crew aboard, heading for Dubai on a scheduled flight, had problems getting off the ground because wrong data had been fed into an onboard computer, according to the Australian Transport Safety Bureau.

The tail of the aircraft struck the runway as the flight crew attempted to get the aircraft off the ground by applying extra thrust.

The Bureau's director of Aviation Safety Investigation, Julian Walsh, said somebody in the cockpit fed into the computer a weight for the aircraft that was 100 tonnes lighter than its actual weight of 362 tonnes.

That meant that the aircraft computer applied vastly less thrust than was needed for the aircraft to climb safely off the runway.

The takeoff was planned as a reduced-power takeoff and the first officer was the handling pilot for the departure, said the Bureau.

Walsh explained, Ã¢â¬ÅâœDuring the take-off the captain called for the first officer to rotate (lift-off). The first officer attempted to rotate the aircraft, but it did not respond immediately with a nose-up pitch.

Ã¢â¬ÅâœThe captain again called 'rotate' and the first officer applied a greater nose-up command. The nose of the aircraft was raised and the tail made contact with the runway surface, but the aircraft did not begin to climb.

Ã¢â¬ÅâœThe captain then selected TOGA (maximum thrust) on the thrust levers, the engines responded immediately, and the aircraft commenced a climb.

Ã¢â¬ÅâœThe crew notified air traffic control of the tail strike and that they would be returning to Melbourne, dumping fuel prior to landing to reduce the aircraftÃ¢â¬â¢s weight.

Ã¢â¬ÅâœWhile reviewing the aircraft's performance documentation in preparation for landing, the crew noticed that a take-off weight, which was 100 tonnes below the actual take-off weight of the aircraft, had inadvertently been entered when completing the take-off performance calculation.

Ã¢â¬ÅâœThe result of that incorrect take-off weight resulted in a thrust setting and take-off reference speeds that were lower than those required for the actual aircraft weight."

The aircraft subsequently landed at Melbourne with no reported injuries.

The Bureau noted that the aircraft made contact with the runway at three separate locations, and one of the aircraft tyres clipped navigation and lighting equipment on the ground.

As a result of the accident, Emirates has advised the Australian Transport Safety Bureau that it is reviewing a number of procedures including human factors involved in take-off performance data entry.

The investigation is continuing. The Bureau said a significant amount of work needed to be done before the release of the final report.

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