Plane's weight blamed for tail scrape

A wrong planeload calculation caused a near disastrous tail-strike by a fully-laden airliner carrying 275 passengers and crew at Melbourne Airport in March.

The incident, described as "a very serious event" by air safety investigators, occurred after a crew member entered incorrect data about the plane's takeoff weight into the aircraft's onboard computer system.

The weight entered was 100 tonnes less than the plane's actual weight of 362 tonnes.

The plane's tail hit the runway on March 20 in three places with two further scrape marks on the grass runoff area.

As well, the plane damaged runway lights and the instrument landing system antenna at the runway's end.

The aircraft returned to Melbourne Airport and landed safely, despite damage to its rear fuselage.

The bureau's director of aviation safety investigation Julian Walsh declined to say just how near the flight came to disaster.

"Speculating on how close it came to crashing is not really that useful," he told reporters in Canberra.

"We all recognise this was definitely a very serious event."

Mr Walsh said the incident occurred as the aircraft accelerated for takeoff.

The aircraft initially failed to respond by lifting its nose. The first officer then applied a greater nose-up command to flight controls, with the nose lifting and the tail striking the runway.

With full engine power applied, it took off and started to climb.

There was no suggestion of any problem with the aircraft, Mr Walsh said.

It was caused because a crew member entered an incorrect figure into the electronic flight bag, a laptop computer which provides data to the aircraft's electronic flight control system.

"We know why the aircraft had the problem. It is because this weight was incorrect," he said.

The correct aircraft weight had been supplied to the crew by ground dispatchers and the investigation was focusing on how the wrong number came to be punched into the computer.

Pilot fatigue did not appear to be a factor.

Neither was the reduced power takeoff, which was standard across airlines and based on procedures developed by aircraft manufacturers.

Mr Walsh said passengers would have noticed something was amiss.

"I would expect that they probably would have heard a bang ... heard scraping noises."

People sitting in seats towards the rear of the plane would have seen some bright flashes.

"There would have been a lot of sparks."

Emirates Airlines says the safety of passengers crew and aircraft is its top priority and the incident is being treated very seriously at the highest levels of the company.

An internal investigation would review how the data input error occurred.

"Emirates existing procedures approved by the manufacturer and regulatory authority, if correctly followed, are indeed very safe," the airline said in a statement.

Emirates has put in place additional physical safeguards to perform independent performance calculations using two computers.

The two pilots involved in incident were forced to resign 48 hours after they were flown back to Dubai.