Air France Flight 4590 was a Concorde flight from Charles de Gaulle International Airport near Paris, France to John F. Kennedy International Airport in New York City, New York, and operated by Air France. On July 25, 2000 it crashed in Gonesse, France. All of the people (100 passengers and 9 crew) on board the flight were killed, as well as four people on the ground.

The flight

As the plane was on its take-off run from Charles de Gaulle Airport, a piece of titanium debris on the runway shredded a tyre, which then burst. A large chunk of tyre (4.5 kg) hit the underside of the aircraft's wing at over 300 km/h, causing the fuel tank above the landing gear to fail from the inside out, possibly by a hydrodynamic pressure surge. Leaking fuel was ignited by an electric arc in the landing gear bay or through contact with the hot parts of the engine (the latter being disputed by the British investigators). At the point of ignition, both engines 1 and 2 surged and instantaneously lost all power, but slowly recovered from 0% over the next few seconds. A large plume of flame developed; the crew then shut down engine 2 in response to a fire warning.

Being past V1 speed, the crew continued the take-off, but they could not gain enough airspeed on the three remaining engines, as the undercarriage could not be retracted. The aircraft was unable to climb or accelerate, and it maintained a speed of 200 knots (370 km/h) at an altitude of 200 feet (60 m). The fire caused damage to the port wing. Engine 1 surged again but this time failed to recover. Due to the asymmetric thrust, the starboard wing lifted, banking the aircraft to over 100 degrees. The crew reduced the power on engines 3 and 4 to attempt to level the aircraft, but with falling airspeed they lost control of the aircraft, crashing into Les Relais Bleus hotel near the airport. The accident killed all 9 crew and 100 (mostly German) passengers and 4 people on the ground.

The crew was trying to divert to nearby Le Bourget Airport, but accident investigators say that a safe landing with the flight path the aircraft was on would have been highly unlikely.

As the CVR transcript recorded it, the last intelligible words of the crew were:

Co-pilot: "Le Bourget, Le Bourget, Le Bourget."

Pilot: "Too late (unclear)."

Control tower: "Fire service leader, correction, the Concorde is returning to runway zero nine in the opposite direction."

Pilot: "No time, no (unclear)."

Co-pilot: "Negative, we're trying Le Bourget" (four switching sounds).

Co-pilot: "No (unclear)."

Concorde grounded

The Concorde had been the safest working passenger airliner in the world according to passenger deaths per distance travelled, although the Boeing 737 fleet acquires more passenger miles and service hours in one week than the Concorde fleet acquired in its entire service career. The crash of the Concorde was the beginning of the end of its career.

A few days after the crash, all Concordes were grounded, pending an investigation into the cause of the crash and possible remedies. Air France Concorde F-BVFC was allowed to return home from its stranded position in New York, empty of passengers.

Investigation

The report of the investigation was published on December 14, 2004, attributing the crash to foreign object damage from a titanium strip that fell from another aircraft, a Continental Airlines DC-10 (N13067) which had taken off four minutes before. According to the report, the piece had not been approved by the US Federal Aviation Administration. However, Continental Airlines maintains that FAA regulations do allow the use of the titanium strip and added that this metal was more wear-resistant than the original part.

British and former French Concorde pilots looked at several other possibilities that the report ignored, including an unbalanced weight distribution in the fuel tanks and loose landing gear. The latter hinted at the Concorde veering off course on the runway, which reduced take-off speed below the crucial minimum. The aircraft had veered very close to a Boeing 747 known to be carrying French President Jacques Chirac. However data from the Flight Data Recorder Black Box indicates that the aircraft was dead centre on the runway and accelerating normally up until the point where the tyre burst occurred. The instantaneous wind speed at the closest anemometer to the take off point was recorded as zero knots.

Modifications and revival

The accident would make way for modifications to be made to Concorde, including more secure electrical controls, Kevlar lining to the fuel tanks, and specially developed, burst-resistant tyres. The new-style tyres would be another contribution to future aircraft development. However, just before services resumed, the September 11, 2001 attacks took place, resulting in a marked drop-off in customers and leading to the eventual end of Concorde flights. Air France stopped flights in in May 2003, while British Airways ended its Concord flights in October 2003.

On March 10, 2005 French authorities began a criminal investigation of Continental Airlines.

As of October 2005, Jacques Herubel, a former Aerospatiale engineer, is under investigation for negligence leading to the crash. A report stated that the company had more than 70 incidents involving Concorde tyres between 1979 and 2000, but had failed to take appropriate steps based upon these incidents.

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