PARIS - A fuel leak that led to the fiery crash of an Air France Concorde jet was probably caused by a strip of metal left on the runway where the supersonic jet took off, investigators said Thursday.
The 16-inch metal piece probably punctured one of the jet's tires, sending heavy chunks of rubber flying into the jet fuel tanks.
The debris - some weighing nine pounds or more - was projected outward and damaged one or several fuel reservoirs on the plane's left wing, causing ''a very important fuel leak and fire,'' said a statement from the Transport Ministry's Accident and Inquiry Office.
The statement, which said the plane was traveling at 195.5 mph at the time the tire burst, shed more light on why the Air France Concorde crashed outside Paris on July 25, plowing into a hotel and killing 113 people.
But it said the exact chain of events that brought the plane down remains to be determined, and that experts still must confirm their theory that the stray 16-inch-long metal piece was responsible for the tragedy. It also did not say where the metal might have come from.
Air France's five remaining supersonic Concorde jetliners have been grounded since the crash, though British Airways' fleet of seven Concordes continue to fly.
French Transport Minister Jean-Claude Gayssot has said the Air France Concordes will not fly again until experts understand exactly what caused the accident.
Investigators on Thursday resumed gathering debris from the site where the Concorde plunged into a hotel in the town of Gonesse. The work had been halted a week ago after cancer-causing asbestos from the doomed aircraft was found in the engines, officials said.
Meanwhile, a report in the British publication New Scientist raised questions about the needle-nosed jet's engines. According to the publication, a 1998 study commissioned by British Airways shows 55 ''significant risks'' inherent in the design of the Concorde engines.
The publication quoted a spokeswoman for British Airways as saying a joint program was under way with Air France to eliminate risks that could lead to a catastrophe. However, New Scientist reported that some of the risks identified in the study - including uncontrolled fire and multiple engine failure - figured into last month's crash.