French aviation experts investigating the Concorde crash that killed 113 people on Tuesday appear to have concluded that the plane was breaking up in the air before the disaster and revealed that parts of a tyre were found on the runway from which it took off.
Although not conclusive, the results of two days' analysis of the "black boxes" - cockpit voice recorder and flight data recorder - strengthen the theory that a foreign object, perhaps a burst tyre, was sucked into the plane's air intake and damaged the engine fans, leading to catastrophic engine failure.
Not one, but both engines on the port side of the aircraft failed. The crew were unable to lift the undercarriage after take-off, and debris was found the entire length of the runway, the transport ministry's Accident Investigation Bureau (BEA) revealed last night.
"The flight data recorder shows that on take-off engine number two lost power to the point that it stopped, and that engine number one temporarily lost power," the BEA said. "It also shows that after this, neither the speed nor the altitude varied much. The plane was in the air a little less than a minute when engine number one showed power loss again. The plane veered sharply to the left and crashed."
There had been wide speculation that the fire in engine two spread to engine one, but the BEA's statement was the first official confirmation that both engines failed. In his last words to the control tower, the pilot, Christian Marty, mentioned failure only in one engine.
Investigators also confirmed the control tower told the crew that the Concorde was on fire only after it had reached the "point of no return" known as V1, beyond which it is impossible to abort take-off. "During the take-off, when the aircraft had passed the point where it could no longer abort, the control tower told the crew that there were flames at the rear of the plane," the statement said.
Once the Concorde reaches 300 k.p.h. it is too late to stop. In a big carrier like the Boeing 747, a pilot has about 30 seconds on the runway before reaching V1; he reaches it twice as quickly in a Concorde, after about 15 seconds.
"Debris was found the entire length of the aircraft trajectory," the BEA reported. "In particular, debris from tyres was found on the runway." This detail suggests that the plane was breaking up during its brief two-minute flight. "In the sound recording, we noted that the crew announced a problem in engine number two and a little later they said the undercarriage would not come up."
Aviation experts believe that the engine fire may have burnt through hydraulic lines, which are located near the wings in the undercarriage. Without hydraulic lines, the landing gear cannot be retracted. The BEA said it is being assisted by British, German and American investigators and will issue a preliminary report at the end of August.
Air France executives and mechanics' unions strongly objected to allegations that repairs carried out on engine two's thrust reverser minutes before the flight took off might have caused the crash. The replacement of the reverser, which helps to brake the engines, was a simple routine operation which could not have led to the fire and crash.
Officials said they had found remains of all 113 people. Air France offered an initial payment of £16,807 to victims' families to help pay for material needs, funerals and psychological care.
