Upon the departure of a Continental Airlines DC-10 from Charles de Gaulle International Airport on 25th July, 2000, a metal wear strip used during a recent repair of the aircraft was dislodged and fell onto the runway. The titanium alloy piece was approximately 1.4 mm thick, a little over an inch wide and roughly 17 inches long. A scheduled 3pm clean-up of the runway failed to take place, and the debris remained where it fell.
French President Jacques Chirac was inbound on a 747 from Japan, following his attendance at a G8 summit. The arrival of his flight forced the adjustment of Air France flight 4590 to a different take-off position on the runway. Shortly after the DC-10 departure flight 4590 began its final run down the runway ready for take-off.
Chartered by a German company, Peter Deilmann Cruises, to connect its passengers to their cruise ship, the MS Deutschland departing from New York for a 16 day voyage to Ecuador, the aircraft carried 100 passengers and nine crew, and was carrying 1790lb excess over the maximum structural weight, and had been loaded so that the centre of gravity was to the rear of the take-off limit.
Reaching a near take off speed of 204mph, the jet tyres hit the discarded strip of metal causing one to puncture. As it disintegrated, a rubber chunk approximately 9.9lbs in weight flew up into the underside of the wing hitting the weakest point in the frame near to the undercarriage, at approximately 310 mph. Although the debris did not penetrate the skin, the shockwave was enough to rupture fuel tank number five, which sat at 94% full.
As fuel leaked rapidly out of the split, a point of ignition developed caused either by an electric spark from the landing gear or via contact with hot engine parts. Engines one and two immediately lost power, although engine one managed to recover. A large body of flames ignited engine two, which the Captain saw, causing him to shut down the engine. Damage from the tyre debris to the landing gear meant that retraction was impossible. As there was not enough runway space to abort the take-off, a minimum of 1.9miles would be needed, the pilot had no choice but to take off with the gear down.
Unable to climb or gain speed, the Air France jet struggled to maintain a height of 60m at only 200 mph, the port side wing began to disintegrate due to the high temperature of the fire, engine one surged once again and shut down, causing an asymmetric thrust to starboard. The jet banked at a 100 degree list to port side with starboard high. In a vain attempt to level the aircraft, the crew reduced the thrust to engines three and four. The engine stalled, speed decreased and control was lost. Air France Concorde flight 4590 ploughed into the nearby Hôtelissimo Les Relais Bleus Hotel, killing all 109 on board, and four staff members in the hotel, critically injuring a fifth.
Flight investigators reports later highlighted a series of errors beginning with the failure to properly maintain the DC-10, whose debris caused the crash, Concorde’s only one in a 27 year history. Criminal charges were brought, John Taylor, the engineer who had fitted the strip was found guilty of negligence and given a 17 month suspended sentence, later overturned. The investigation concluded that the outlaying factors of weight and the issue with the landing gear did not directly affect the outcome of the crash, and that even without the lack of power to two engines, the damage to the aircraft by the tyre blowout would have made the crash inevitable. Had the pilots made the decision to abort the take-off, the lack of runway and the travelling speed would have made the landing gear unstable, and probable to collapse, meaning a ground impact was also unavoidable.
In simple terms, from the point of impact of the illustrious supersonic aircraft, with the small strip of metal, very similar in size to a doorway carpet connector strip, and given alternative variables, there would be only one outcome.
Later reports released showed that the rupture of tyres had occurred on at least four separate occasions in the past, and that a design fault with the structure meant that modifications to reinforce the skin thickness in the fragile area would add weight and negate the functionality of the flapless structure. Concorde was designed with slat and flap free form, to reduce weight but as a result needed to achieve higher air and tyre speeds.
It has been claimed that a “spacer” that fit between the landing gear, to keep the wheels aligned, had been left off the Concorde during its routine service, and that this may have contributed to the accident, as without it, the landing gear hitting the FOD caused the wheels to buckle slightly disabling their retraction further. But following the previous incidents a directive had been issued for emergency situations such as these, that the safest procedure was to take off with the landing gear down, therefore the lack of spacer, and the position of the landing gear was not considered a contributory factor.
It was then confirmed that Henri Perrier, head of the Concorde program, chief engineer Jacques Herubel and Claude Frantzen, head of French airline regulator DGAC were all aware that there was a high possibility of fuel tank rupture from damage caused by foreign objects. Charges were laid against the three, but they were later cleared. Continental airlines were ordered to pay damages by a civil court ruling for causing the debris which led to the accident.
Modifications, particularly to the tyres were made, however before the grounded Concorde fleet could resume commercial flight, terrorist attacks on the World Trade Centre in New York, had a negative effect on passenger flight numbers postponing the re-launch. Air France had been allegedly running at a loss, preferring to use the prestige of the aircraft to negate losses of revenue. By October 2003, all Concorde services were finished.