Air France Flight 4590 was a scheduled international flight from Paris, France, to New York City, on the Aérospatiale-BAC Concorde. On 25 July 2000, at time 16:43 CET, the aircraft serving the flight, registration F-BTSC, ran over debris on the runway during takeoff, blowing a tyre and puncturing a fuel tank, leading to fire and engine failure. All 100 passengers and nine crew members aboard the Concorde died when it crashed into a hotel in nearby Gonesse; on the ground, four people were killed and one was critically injured.
The flight was chartered by German company Peter Deilmann Cruises; the passengers were on their way to board the cruise ship MS Deutschland in New York City for a 16-day cruise to Manta, Ecuador. This was the only fatal Concorde accident during its 27-year operational history.
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Event summary
Post-accident investigation revealed that the aircraft was at or over the maximum takeoff weight for ambient temperature and other conditions, and 810 kilograms (1,790 lb) over the maximum structural weight. As it left the gate, it was loaded such that the centre of gravity was aft of the take-off limit. Fuel transfer during taxiing left the number five wing tank 94% full. A 12-inch spacer that normally keeps the left main landing gear in alignment had not been replaced after recent maintenance; however, the French Bureau for Accident Investigation concluded that this did not contribute to the accident. The wind at the airport was light and variable that day, and was reported to the cockpit crew as an eight knot tailwind as they lined up on runway 26R.
Five minutes before the Concorde departed, a Continental Airlines DC-10 heading for Newark, New Jersey took off from the same runway and lost a titanium alloy strip (part of the engine cowl, identified as a wear strip) that was about 435 millimetres (17.1 in) long, 29 to 34 millimetres (1.1 to 1.3 in) wide and 1.4 millimetres (0.055 in) thick.
During the Concorde's takeoff run, it ran over this piece of debris, cutting a tyre and sending a large chunk of tyre debris (4.5 kilograms or 9.9 pounds) into the underside of the aircraft's wing at an estimated speed of 140 metres per second (310 mph). Although it did not directly puncture any of the fuel tanks, it sent out a pressure shockwave that ruptured the number five fuel tank at the weakest point, just above the undercarriage. Leaking fuel gushing out from the bottom of the wing was most likely ignited by an electric arc in the landing gear bay or through contact with hot parts of the engine. Engines one and two both surged and lost all power, but engine one slowly recovered over the next few seconds. A large plume of flame developed; the flight engineer then shut down engine two in response to a fire warning and the captain's command. Air traffic controller Gilles Logelin noticed the flames before the Concorde was airborne, however with only 2 km (1.2 mi) of runway remaining and travelling at a speed of 328 km/h (204 mph), its only option was to take off. The Concorde would have needed at least 3 km (1.9 mi) of runway to abort safely.
Having passed V1 speed, the crew continued the takeoff, but the plane did not gain enough airspeed with the three remaining engines, because damage to the landing gear bay door prevented the retraction of the undercarriage. The aircraft was unable to climb or accelerate, maintaining a speed of 200 knots (370 km/h; 230 mph) at an altitude of 60 metres (200 ft). The fire caused damage to the port wing, which began to disintegrate--melted by the extremely high temperatures. Engine number one 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 three and four in an attempt to level the aircraft, but with falling airspeed they lost control and the aircraft stalled, crashing into the Hôtelissimo Les Relais Bleus Hotel near the airport.
The crew was trying to divert to nearby Le Bourget Airport, but accident investigators stated that a safe landing, given the aircraft's flight path, would have been highly unlikely.
As the cockpit voice recorder (CVR) transcript recorded it, the last intelligible words in the cockpit (translated into English) were:
Hotels Near Cdg Airport Video
Fatalities
All the passengers and crew were killed in the incident. Four employees of the Hotelissimo hotel were also killed in the incident. Most of the passengers were German tourists en route to New York for a cruise.
The cockpit crew consisted of pilot Captain Christian Marty, 54, First Officer Jean Marcot, 50, and Flight Engineer Gilles Jardinaud, 58.
Concorde grounded
Up until the crash of Air France Flight 4590 in 2000, the Concorde SST had been considered among the world's safest planes. The crash of the Concorde contributed to 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's Concorde operation had been a money-losing venture, but it is claimed that the airplane had been kept in service as a matter of national pride; British Airways, however, claimed to make a profit on its Concorde operations. According to Jack Lowe, a Concorde pilot, up until the crash of Air France Flight 4590 at Paris, the British Airways Concorde operation made a net average profit of about £30m a year. Commercial service was resumed in November 2001 after a £17m safety improvement service, until the remaining aircraft were retired in 2003.
Accident investigation
The official investigation was conducted by France's accident investigation bureau, the BEA, and it was published on 16 January 2002.
Conclusions
The investigators concluded that:
- The aircraft was overloaded by 810 kilograms (1,790 lb) above the maximum safe takeoff weight. Any effect on takeoff performance from this excess weight was negligible.
- After reaching takeoff speed, the tyre of the number 2 wheel was cut by a metal strip (a wear strip) lying on the runway, which had fallen from the thrust reverser cowl door of the number 3 engine of a Continental Airlines DC-10 that had taken off from the same runway five minutes previously. This wear strip had been replaced at Tel Aviv, Israel, during a C check on 11 June 2000. Further maintenance work had been performed at Houston, Texas, but the strip had been neither manufactured nor installed in accordance with the procedures as defined by the manufacturer.
- The aircraft was airworthy and the crew were qualified. The landing gear that later failed to retract had not shown 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.
- Aborting the takeoff 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.
Previous tyre incidents
In November 1981, the American National Transportation Safety Board sent a letter of concern to the French BEA that included safety recommendations for Concorde. This communiqué was the result of the NTSB's investigations of four Air France Concorde incidents during a 20-month period from July 1979 through to February 1981. The NTSB described those incidents as "potentially catastrophic," because they were caused by blown tyres during takeoff. The NTSB also expressed concern about the lack of adequate remedies on the part of the French, as well as improper crew responses to those incidents. During its 27 years in service, Concorde had about 70 tyre- or wheel-related incidents, 7 of which caused serious damage to the aircraft or were potentially catastrophic.
- 13 June 1979: The number 5 and 6 tyres blew out during a takeoff from Washington Dulles International Airport. Fragments thrown from the tyres and rims damaged number 2 engine, punctured three fuel tanks, severed several hydraulic lines and electrical wires, and tore a large hole on the top of the wing over the wheel well area
- 21 July 1979: Another blown tyre incident during takeoff from Dulles Airport. After that second incident the "French director general of civil aviation issued an air worthiness directive and Air France issued a Technical Information Update, each calling for revised procedures. These included required inspection of each wheel and tyre for condition, pressure and temperature prior to each takeoff. In addition, crews were advised that landing gear should not be raised when a wheel/tyre problem is suspected."
- August 1981: British Airways (BA) plane taking off from New York suffered a blow-out, damaging landing gear door, engine and fuel tank.
- November 1985: Tyre burst on a BA plane leaving Heathrow, causing damage to the landing gear door and fuel tank. Two engines were damaged as a result of the accident.
- January 1988: BA plane leaving Heathrow lost 10 bolts from its landing gear wheel. A fuel tank was punctured.
- July 1993: Tyre burst on a BA plane during takeoff at Heathrow, damaging the landing gear, wing, fuselage and wiring.
- October 1993: Tyre burst on a BA plane during taxi at Heathrow, puncturing wing, damaging fuel tanks and causing a major fuel leak.
Because it is a tailless delta-wing aircraft, Concorde cannot use the normal flaps or slats to assist takeoff and landing, and requires a significantly higher air and tyre speed during the takeoff roll than the average airliner. That higher speed increased the risk of tyre explosion during takeoff. When the tyres did explode, much greater kinetic energy was carried by the resulting fragments, increasing the risk of serious damage to the aircraft. A thicker skin on the bottom side of the wings could have prevented serious damage from an exploding tyre, but that would have added too much weight, therefore requiring an even higher speed to become airborne.
Modifications and revival
The accident led to modifications being 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.
The crash of the Air France Concorde nonetheless proved to be the beginning of the end for the type. Just before service resumed, the 11 September attacks took place, resulting in a marked drop in passenger 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.
In June 2010, two groups attempted, unsuccessfully, to revive Concorde for "Heritage" flights in time for the 2012 Olympics. The British Save Concorde Group, SCG, and French group Olympus 593 were attempting to get four Rolls-Royce Olympus engines at Le Bourget Air and Space Museum in France.
Criminal investigation
French authorities began a criminal investigation of Continental Airlines, whose plane dropped the debris on the runway, in March 2005, and in September of that year, Henri Perrier, the former chief engineer of the Concorde division at Aérospatiale at the time of the first test flight in 1969 and the programme director in the 1980s and early 90s, was placed under formal investigation.
In March 2008, Bernard Farret, a deputy prosecutor in Pontoise, outside Paris, asked judges to bring manslaughter charges against Continental Airlines and two of its employees - John Taylor, the mechanic who replaced the wear strip on the DC-10, and his manager Stanley Ford - alleging negligence in the way the repair was carried out. Continental denied the charges, and claimed in court that it was being used as a scapegoat by the BEA. The airline suggested that the Concorde "was already on fire when its wheels hit the titanium strip, and that around 20 first-hand witnesses had confirmed that the plane seemed to be on fire immediately after it began its take-off roll".
At the same time charges were laid against Henri Perrier, head of the Concorde program at Aérospatiale, Jacques Hérubel, Concorde's chief engineer, and Claude Frantzen, head of DGAC, the French airline regulator. It was alleged that Perrier, Hérubel and Frantzen knew that the plane's fuel tanks could be susceptible to damage from foreign objects, but nonetheless allowed it to fly.
The trial ran from February to December 2010. Continental Airlines was found criminally responsible for the disaster by a Parisian court and was fined EUR200,000 ($271,628) and ordered to pay Air France EUR1 million. Taylor was given a 15-month suspended sentence, while Ford, Perrier, Hérubel and Frantzen were cleared of all charges. The court ruled that the crash resulted from a piece of metal from a Continental jet that was left on the runway; the object punctured a tyre on the Concorde and then ruptured a fuel tank. The convictions were overturned by a French appeals court in November 2012, thereby clearing Continental and Taylor of criminal responsibility.
The Parisian court also ruled that Continental would have to pay 70% of any compensation claims. As Air France has paid out EUR100 million to the families of the victims, Continental could be made to pay its share of that compensation payout. The French appeals court, while overturning the criminal rulings by the Parisian court, affirmed the civil ruling and left Continental liable for the compensation claims.
Alternative theories
British investigators and former French Concorde pilots looked at several factors that the BEA found to be of negligible impact: 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 takeoff speed below the crucial minimum. John Hutchinson, who had served as a Concorde captain for 15 years with British Airways, said that "the fire on its own should have been 'eminently survivable; the pilot should have been able to fly his way out of trouble'", had it not been for a "lethal combination of operational error and 'negligence' by the maintenance department of Air France" that "nobody wants to talk about".
The Concorde had veered close to an Air France Boeing 747 carrying then-French President Jacques Chirac who was returning from the 26th G8 summit meeting in Okinawa, Japan, which was much further down the runway than the Concorde's usual takeoff point; only then did it strike the metal strip from the DC-10.
The Concorde 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 tyres skewed the landing gear, with the scuff marks of four tyres on the runway showing that the plane was veering to the left. Air France found out that its maintenance staff had not replaced or renewed the spacer, which was found in a workshop after the crash.
The BEA investigation on Air France Flight 4590 failed to address a 1981 report from the USA's National Transportation Safety Board (NTSB), which criticized Air France for its "lax procedures and a lack of action being taken to remedy the causes of four potentially catastrophic tire bursts which had occurred during Concorde take-offs". British Airways, the only other Concorde operator, took measures to minimize such risks.
Legacy
One monument in honour of the crash victims was established at Gonesse. The Gonesse monument consists of a piece of transparent glass with a piece of an aircraft wing jutting through. Another monument, a 6,000-square-metre (65,000 sq ft) memorial topiary in the shape of a Concorde, was established in 2006 at Mitry-Mory.
In media
- The timeline and causes of the crash were profiled in the premiere episode of the National Geographic documentary series, Seconds From Disaster.
- NBC aired a Dateline NBC documentary on the crash, its causes, and its legacy on 22 February, 2009.
- Channel 4 and Discovery Channel Canada aired a documentary called Concorde's Last Flight.
- Smithsonian Channel aired a 90-minute documentary Concorde: Flying Supersonic in 2010.
- The aircraft that crashed had previously been used in the making of the movie The Concorde ... Airport '79.
- The accident and subsequent investigation were featured in the 13th-season episode of documentary series Mayday (also known as Air Crash Investigation) titled "Concorde: Up In Flames", first broadcast in January 2015.
Source of the article : Wikipedia
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