Engine repair 'left no time for testing of work'

An aerospace engineer said yesterday that the faulty replacement of a part on the crashed Concorde, carried out hours before it took off, could be the direct cause of the disastrous explosion in its left wing.

An aerospace engineer said yesterday that the faulty replacement of a part on the crashed Concorde, carried out hours before it took off, could be the direct cause of the disastrous explosion in its left wing.

The engineer, who works for a major aerospace company, said the speed with which the repair was done would have left no time for testing that could have identified a faulty fitting.

Captain Christian Marty had ordered the replacement of the thrust reverser on the No 2 engine on the inside of the left wing. This had failed on an earlier inbound flight, and a replacement part had to be found. The job took 30 minutes.

The reverser slows the aircraft as it lands by closing over the exhaust, redirecting its thrust forwards. French newspapers said investigators had seized maintenance documents relating to the repair work.

"They wouldn't have changed the whole thrust reverser, because that would take hours, but probably changed a small control motor that controls the position of the reversers," said the engineer, who contacted The Independent, and asked not to be named. "If it was incorrectly fastened, that could have operated the jack that closes the reversers. Normally you would carry out a test with the engines running, but if they didn't, that could be what malfunctioned."

In 1991 a Lauda Air Boeing 767 crashed into the sea, killing all on board, when a thrust reverser deployed accidentally 45 minutes into flight.

Rolls-Royce and other aero-engine companies are refusing to comment, or to provide details of Olympus enginesand their maintenance, until the French inquiry releases its details. Investigators were yesterday reviewing 600 pieces of data from the flight recorder and drawing up transcripts of the cockpit voice recorder.

The engineer said that if the thrust reverser came on during take-off, when the engines are developing maximum thrust, it would be "like revving your car with the clutch off and then slamming it into gear". The resulting blowback might have torn the engine apart.

Another expert disagreed, however. Bill Ganston, editor of reference book All The World's Aircraft Engines, said: "This was definitely an uncontained failure" - meaning that something broke off inside the engine and punctured the fuel tanks.

An Air France executive, Franck de Bouq, said he found it hard to see a connection between the replacement of the motor and the flames that engulfed that wing minutes later. "A faulty engine does not jeopardise either take-off nor a return to land. So as far as I can see there must have been another problem, more serious, on one or two engines," he said.