Paris Crash

Air France Flight 4590

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 25 July 2000 it crashed in Gonesse, France. All 100 passengers and nine crew on board the flight, as well as four people on the ground, were killed.

This amateur photograph shows the fuel tank on fire

The flight was chartered by German company Peter Deilmann Cruises and all passengers were on their way to board the MS Deutschland cruise ship in New York City for a 16-day cruise to South America.

Flight

During the plane's take-off run from Charles de Gaulle Airport, a piece of titanium debris from a previous flight on the runway ruptured a tyre as the Concorde accelerated to 323 km/h, which subsequently burst. The debris was about three centimetres wide and 43 centimetres long. A large chunk of tyre (4.5 kg) struck the underside of the aircraft's wing structure at well over 300 km/h. This lethal debris carried the energy in excess of twenty .44 Magnum gun blasts. This impact dented the wing and created pressure waves in the fuel tank that propagated and caused a rupture elsewhere in fuel tank number 5, just above the landing gear. Leaking fuel was ignited by an electric arc in the landing gear bay or through contact with severed electrical cables. At the point of ignition, engines 1 and 2 both surged and lost all power, but slowly recovered over the next few seconds. A large plume of flame developed; the crew then shut down engine 2 in response to a fire warning.

Having passed V1 speed, the crew continued the take-off but they could not gain enough airspeed on the three remaining engines, because 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, crashing into the Hôtelissimo Les Relais Bleus Hotel near the airport.

The crew was trying to divert to nearby Le Bourget Airport; 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 (translated into English):

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 niner 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. The crash of a Concorde was the beginning of the end of the aircraft's 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.

Accident investigation

The official investigation was conducted by France’s accident investigation bureau, the BEA, and it was published on 14 December 2004. It concluded that the crash was caused by a titanium strip, part of a thrust reverser, that fell from a Continental Airlines DC-10 (Continential Flight 55) that had taken off about four minutes earlier to Houston. This metal fragment punctured the Concorde's tyres, which then disintegrated. A piece of rubber hit the fuel tank and broke an electrical cable. The impact caused a shockwave that fractured the fuel tank some distance from the point of impact. This caused a major fuel leak from the tank, which then ignited. The crew shut down engine number two in response to a fire warning but were unable to retract the landing gear, which hampered the aircraft's ability to climb. With engine number one surging and producing little power, the aircraft was unable to gain height or speed, entering a rapid pitch-up then a violent descent, rolling left. The impact occurred with the stricken aircraft tail-low, crashing into the Hotelissimo Hotel in Gonesse. According to the report, the piece of titanium from the DC-10 had not been approved by the U.S. Federal Aviation Administration.

Conclusions

The investigators concluded that:

  • The aircraft was airworthy and the crew was qualified. The landing gear that later failed to retract did not show serious problems in the past. Despite the crew being trained and certified, no plan existed for the simultaneous failure of two engines on the runway, as it was considered highly unlikely.
  • The aircraft was slightly overloaded, being about a tonne too heavy.
  • After reaching take-off speed, the tyre of the number 2 wheel was cut by a metal strip lying on the runway, which came from the thrust reverser cowl door of the number 3 engine of a Continental Airlines DC-10 that had taken off from the runway several minutes before. This strip was installed in violation of the manufacturer's rules.
  • Aborting the take-off would have led to a high-speed runway excursion and collapse of the landing gear, which also would have caused the aircraft to crash.
  • While two of the engines had problems and one of them was shut down, the damage to the plane's structure was so severe that the crash would have been inevitable, even with the engines operating normally.

Alternative theories

British investigators 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. They came to the conclusion that the Concorde veered off course on the runway, which reduced take-off speed below the crucial minimum. The aircraft had passed close to a Boeing 747 known to be carrying French President Jacques Chirac who was returning from the 26th G8 summit meeting in Okinawa, Japan.

They argued that the Concorde was in trouble before takeoff, as it was overweight for the given conditions, with an excessively aft center of gravity and taking off downwind. They claim that when it stood at the end of the runway, ready to roll, it was more than six tonnes over its approved maximum takeoff weight for the given conditions.

Moreover, it was missing the crucial spacer from the left main landing-gear beam that would have made for a snug-fitting pivot. This compromised the alignment of the landing gear and the wobbling beam and gears allowing three degrees of movement possible in any direction. The uneven load on the left leg’s three remaining tires skewed the landing gear disastrously, with the scuff marks of four tires on the runway showing that the plane was skidding out of control.

Finally, Brian Trubshaw and John Cochrane, the Concorde's two test pilots when the aircraft was being developed in the early 1970s, set the aft operating limit at 54 per cent - beyond that, they found, it risked becoming uncontrollable, likely to rear up backwards and crash, exactly as Flight 4590 did in its final moments over Gonesse. However, Flight 4590's centre of gravity went beyond 54 per cent, with the BEA stating a figure of 54.2 per cent, while a senior industry source said that the true figure may have been worse: with the extra fuel and bags, it may have been up to 54.6 per cent.

These investigators were frustrated by the lack of cooperation from French authorities, including an unwillingness to share data and the immediate resurfacing of the Concorde's takeoff runway after the crash. They alleged that the BEA was determined to place the sole blame of the accident on the titanium strip to show that the Concorde itself was not at fault. The piece of metal from the DC-10 was found 7 meters forward, and 37 meters to the right of where the Concorde's tyre blew.

The BEA's interim report maintained that the leftward yaw was caused not by incorrectly assembled landing gear but by loss of thrust from the number 1 and 2 engines. Data from the Flight Data Recorder Black Box indicates that the aircraft was centred 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 led to modifications being made to the 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. Just before services resumed, the September 11, 2001 attacks took place, resulting in a marked drop in customer numbers, and contributing to the eventual end of Concorde flights. Air France stopped flights in May 2003, while British Airways ended its Concorde flights in October 2003.

Criminal investigation

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

In September 2005, Henri Perrier, the former head of the Concorde division at Aerospatiale, and Jacques Herubel, the Concorde chief engineer, came under investigation for negligence: 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.

On 12 March 2008, Bernard Farret, a deputy prosecutor in Pontoise, outside Paris, asked judges to bring manslaughter charges against Continental Airlines and four individuals:

  • John Taylor, a Continental mechanic
  • Stanley Ford, a Continental maintenance manager
  • Henri Perrier of Aerospatiale
  • Claude Frantzen, a former employee of the French airline regulator.

Charges against Jacques Herubel were dropped.

On 3 July 2008, confirmation of the trial, including Jacques Herubel, was published which is due to commence in 2009 and is expected to last two to three months.