Investigators searching for the cause of the Air France Concorde crash combed through wreckage and examined debris in high-tech labs Saturday, trying to confirm whether a tire explosion could have triggered its fiery plunge.
A tire blew out on the supersonic jet's undercarriage as it raced down the runway at Charles de Gaulle airport for takeoff, France's Transport Ministry confirmed Friday.
Efforts forged ahead at the crash site and in scientific labs Saturday to determine whether the blown tire started the deadly chain of events that led to an engine breakdown and the crash that killed 114 people, a spokesman at the ministry's Accident and Inquiry office said.
French officials raised the death toll by one Friday after discovering another body beneath the rubble of a hotel struck by the crashing Concorde. The victim's sex and nationality were not immediately identifiable. Four other bystanders died when the plane slammed into the hotel in Gonesse, a town near the airport.
A preliminary report on Tuesday's crash is due to be published at the end of August, but just three days after the tragedy, a sketchy image of the sequence of events has surfaced.
"At least one tire exploded, which could have triggered a chain of events, structural damages, a fire and an engine breakdown," the Transport Ministry said Friday.
The Accident and Inquiry Office earlier said that one or two of the wheels on the left side landing gear may have blown out and that the fire that ravaged the jetliner did not necessarily start in the engines.
An initial report from the ministry on Thursday had raised the specter of something as mundane as a puncture being involved. It said tire debris had been found strewn along the runway.
Investigators know that engine No. 2 failed, that the pilot could not draw up the undercarriage and that engine No. 1 lost power -- once on the runway, and again, fatally, less than one minute into the flight. The Concorde has four engines, two under each wing.
Blown-out tires have been blamed for past brushes with near-disaster, despite Concorde's seemingly spotless safety record.
In 1981, the U.S. National Transportation Safety Board reported five "potentially catastrophic" incidents resulting from blown-out tires during Concorde takeoffs between June 1979 and February 1981.
Despite its excellent safety record, the Concorde is famously "fragile" and according to a report Saturday in the Paris daily, Liberation, requires exhaustive maintenance that accounts for 50 percent of the plane's operation cost, compared to around 10 percent for most other planes.
Most of the 100 passengers aboard flight AF4590 were German tourists headed to New York to board a luxury cruise to the Caribbean.
Friends and colleagues of the nine crew members who died in the crash attended a memorial service Friday at Air France's headquarters at the Charles de Gaulle airport.
Speakers praised the crew's professionalism. Many of the mourners bowed their heads, others cried in their handkerchiefs. One woman fainted.
"It was a very moving ceremony," said Gerard Feldzer, an Air France pilot. "Each one of us was touched."
In Gonesse, residents walked silently in a procession from the town hall toward the site where the Concorde went down in a ball of fire.
Mayor Jean-Pierre Blazy walked at the front with the owner of the destroyed hotel, Michele Fricheteau, whose arms were wrapped in white bandages and face was scattered with burns.
"We're still in shock. It's a time for reverent silence, pain and emotion," Blazy said.
Transport Minister Jean-Claude Gayssot, who has grounded all Air France Concorde flights, said Friday he wanted across-the-board supplementary security procedures before allowing the supersonic jets to take to the sky again.
Air France said its jets would remain grounded until further notice.