A French manslaughter trial probing a deadly Concorde crash blamed on a strip of metal lying on the runway heard on Wednesday that inspectors had failed to check the runway before the disaster.

Three runway checks were supposed to be carried out each day, the court was told, but no inspection had been carried out for nearly 12 hours before the supersonic jet took off at 4.42pm on 25 July 2000.

"The day of the accident, the last inspection was carried out at 5am in the morning," Judge Dominique Andreassier said, reading out documents presented to the court in Pontoise, near Paris.

The afternoon inspection had not been carried out on runway 26 at Paris Charles de Gaulle airport because a fire drill was being conducted, she said.

The trial opened on Tuesday with French engineers who built the Concorde in the dock alongside Continental Airlines mechanics accused of causing the crash that sounded the death knell for supersonic travel.

The US airline and two of its technical staff are accused of the manslaughter of 109 people on the plane ? most of them German tourists ? and four hotel workers on the ground.

A former French civil aviation official and two former Concorde engineers face the same charges in the mammoth trial expected to last four months and cost more than three million euros ($4.2-million).

All parties deny any wrongdoing.

A strip of metal to blame?

The court will decide whether to side with investigators and technical experts who say the crash was caused by a metal strip that fell off a Continental DC-10 that took off on the same runway just minutes before the Concorde.

The strip shredded a tyre, causing a blow-out and sending debris flying into an engine and a fuel tank and setting it on fire, according to investigators.

The court will also ask whether the French aviation official and the two engineers failed to correct faults on the supersonic jet favoured by the rich and famous for their trans-Atlantic trips.

Continental's lawyer Olivier Metzner has promised to present witnesses ? including firemen based at the airport ? who would testify that the New York-bound plane was on fire well before it reached the metal strip.

Metzner said on Tuesday that "there is an attempt to protect the Concorde and the image that it projected of France" and that it was absurd to blame the crash on a small metal strip.

Continental could receive a maximum fine of ?375 000 ($525 000) if found guilty. The individuals, who all deny the charges, face up to five years in jail and a fine of up to ?75 000.

Most of the families of the people who died in the crash agreed not to take legal action in exchange for compensation from Air France, the EADS aerospace firm, Continental and Goodyear tyre maker.

The Concorde made its maiden commercial flight in 1976. Only 20 were made ? six for development and the remaining 14 for flying mainly trans-Atlantic routes at speeds of up to 2170 kilometres an hour.

Air France and BA grounded their Concordes for 15 months after the crash and, after a brief resumption, finally ended the world's only supersonic commercial service in 2003.

Judge Andreassier on Wednesday postponed a decision on whether to call off the manslaughter trial as demanded by Metzner, who claims the eight-year judicial inquiry that preceded it was allegedly skewed against the US airline.

She said she would wait until the final stages of the proceedings before determining whether to declare the proceedings null and void, prior to giving her verdict.