The crash, in which all seven occupants were killed - including Airbus's chief test pilot, Nick Warner, an Englishman - occurred after the plane plunged from a height of 400m (1,300ft).
The fatal test involved simulating the failure of the left-hand engine and its hydraulics immediately after take-off, while the aircraft was already travelling under extreme conditions, climbing at an angle of 28 compared with the normal trajectory of 18, and with ballast pushing the centre of gravity towards the back of the plane.
The operation was intended to test how quickly the autopilot restored the plane to level flying after the inevitable lurch caused by the shutting down of one engine. Clearly the autopilot failed to react quickly enough, and the pilot took over the controls in a final attempt to save the plane, managing to level it out just as it hit the ground. But the slow speed of 117mph did not allow sufficient time for recovery.
Such tests used to be a requirement for all pilots, but were replaced by trials in the simulator after several crashes in the 1960s, and are now only needed for certificating new types of aircraft with the aviation authorities.
A team of 40 investigators is trying to discover the cause. Mr Warner was known by fellow fliers as one of the world's best test pilots. One said: 'He would have known exactly what he was doing and what to expect. He was not only an excellent pilot, but a very knowledgeable engineer. He must have been taken by surprise by the aircraft's handling.' Mr Warner had been with Airbus as a test pilot since 1985 and was chief test pilot with the Civil Aviation Authority from 1981 to 1985.
Robert Alizart, vice-president (communications) of Airbus Industrie, said yesterday that the test was unlikely to be repeated under such extreme conditions. He said: 'I don't know when that will be as we do not have another A330 fitted out with Pratt & Whitney engines.'
Several A330s are already in service but they are all powered by General Electric engines. Different engines require separate certification.
The fatal test was one of the last parts of the certification process and was needed to allow the plane to land - and if necessary, abort a landing - in conditions of poor visibility.
There had been previous problems with the Pratt & Whitney engine involving the reverse-thrust mechanism which has delayed the certification process, but it is not known if this is a related problem.
One industry source said: 'It is very unusual for Airbus to complete its certification process, and therefore deliver its first planes, late.'
A330s are wide-bodied twin-engine jets with a range of about 4,500 miles and capable of carrying 335 passengers.
Although there have now been 10 crashes involving Airbus planes over the past six years, there is no pattern to these incidents and they have involved different types of aircraft.Reuse content