The Trent 900 has performed successfully in ground tests

The engines have been specially adapted for use on an A340-300 jet in Toulouse in order for them to be flight tested.

These checks are designed to prove the performance of the engine on a real aircraft following a successful round of ground-testing at Rolls-Royce.

New technology provides constant in-flight data on the engine's health.

"This is a significant milestone for the A380's lead engine," said Charles Cuddington, managing director (airlines) for Rolls-Royce.

"We've seen some excellent results from testing already completed - the best from any Trent at this stage of development."

The engine will provide 70,000 lbs of thrust at take-off and its makers claim it is the world's cleanest large turbofan engine measured by emissions per pound of thrust.

The manufacturer has also been working to reduce noise emissions from the engine in order to meet regulations for departure at London airports.

The Trent 900's Quick system, which provides constant data on how the engine performs in-flight, will help maintenance teams anticipate problems before they become aggravated.

In previous tests at Rolls-Royce test beds, the Trent 900 coped successfully with the simulated ingestion of a bird and with a "blade off" test, in which a fan blade is deliberately fired loose.

The A380 can seat about 555 people, about 155 more than current jumbos.

The Trent 900 will be used on 48% of Airbus A380s so far ordered. The other planes will use US Pratt & Whitney engines.