LONDON — Today in Aviation, Air France (AF) flight AF4590 crashed moments after taking off from Paris-Charles de Gaulle Airport (CDG) in 2000, marking the beginning of the end of Concorde in civilian use.
In the July/August 2020 issue of Airways, Andreas Spaeth interviews Captain Jean-Louis Châtelain, an AF Captain of the Concorde, and a member of the investigation team for AF4590. The flight was operated by a BAe/Aerospatiale Concorde.
All information regarding the probable causes and recommendations have been obtained from the English version of the BEA’s final report.
The Concorde Project
While today we take full advantage of the cross-border aerospace sector within Europe, the Concorde project was the beginning. Airbus owes much of its current state to this project.
Concorde was developed and produced between the French and British as an advanced project. The agreement was signed as an international treaty due to the current political climate of the time.
The design of the Concorde was more similar to fighter aircraft, with a delta wing and pointed nose. In the 1960s it was revolutionary. The Concorde was the beginning of commercial aircraft using fly-by-wire technology, the same technology that Airbus uses to this day.
While perhaps Concorde was not a commercial success in the traditional sense, the aircraft itself broke engineering barriers for commercial flight. It was the only passenger aircraft to fly faster than the speed of sound, although the passenger cabin was cramped. The Concorde entered service in 1976.
24 Years of Safety
During its operational career, the Concorde was regarded as a safe aircraft, despite various potentially catastrophic incidents with blown tires. Most of them occurred during the first five years of its entry into service, but little or no changes were made to enhance the safety of the jetliner.
During 24 years, passengers would enjoy a First Class experience aboard the Concorde, while observing the curvature of the earth at 60,000 feet, traveling twice the speed of sound. Unfortunately, on the afternoon of July 25, 2000, the public perception of the public on the Concorde changed in 82 seconds.
After the Air France 4590 crash, Concordes were grounded for inspection and enhanced safety features. Unfortunately, the aircraft found a very different scenario, with the post 9/11 crisis hitting the travel industry and spiking fuel prices. Concorde, and its promise of supersonic travel, was phased out of service in 2003.
The Concorde is an icon that marked the crossroads in the history of air transport. In the times where speed was competing with capacity, the Concorde found itself a place in history as the epitome of luxury in air travel.
However, there never was a market for the type, as airlines embarked into the widebody era with the Boeing 747, and lately the McDonnell Douglas DC-10 and Lockheed L1011 Tristar.
Air France AF4590: A Chronology of the Crash
In the afternoon of July 25, 2000, Air France flight AF4590 was readying its departure from Paris-Charles de Gaulle Airport bound to New York-JFK. A German Cruise company chartered two Concorde flights, as most of the passengers were hen going to board a ship sailing to Ecuador.
The Flight crew for AF4590 was Captain Christian Maury, First Officer Jean Marcot, and Flight Engineer Gilles Jardinaud. Altogether, they had over 36,000 flight hours of experience. Of these, over 3,900 were in Concorde.
AF4590 was the second charter flight due to depart that day. Air France assigned the flight to F-BTSC (MSN 103). According to the records from the airline, F-BTSC had just received an “A” check four days before the accident and had logged 11,989 flight hours and 3,978 landings.
At 13:58, Flight 4590 contacted ATC for clearance to take off at 14:30. The takeoff was requested for the full length of runway 26.
At 14:42, takeoff roll commenced, and a few seconds after reaching V1, the speed by which time the decision to continue flight if an engine fails has been made, the aircraft ran over foreign object debris on the runway.
This foreign object, which was a strip of metal, sliced into the front left tire on the left main landing gear. This strip of metal had fallen from a DC-10 which had taken off a few minutes earlier.
Cause of the Fire
Investigators determined that the foreign object debris was a strip of metal, which sliced into the front left tire on the left main landing gear. The bursting of the tire launched large pieces of rubber into the lower part of the left-wing, rupturing fuel tank five.
The subsequent fuel leak caused a fire. Engine two lost thrust, and engine one lost thrust after the fire broke out. This loss of thrust is believed to be due to the injection of hot gases and fuel, as well as debris intake. However, at the same time, the pilot rotated the aircraft and took off.
After the aircraft left the runway, the controller alerted the crew of the fire. The crew then pulled the fire handle on engine 2. The Pilot Flying requested gear up, which was unsuccessful due to the gear doors not working properly.
Air Traffic again reported large flames. Due to the aircraft’s configuration, the aircraft was unable to climb or gain speed. This was further hindered by the loss of engine 1.
Less than a minute later after the failure of engine 1, Flight 4590 crashed into a hotel outside the airfield in Gonesse, a commune in northeastern Paris.
All 109 passengers and crew perished in the crash, and four people on the ground were also fatally injured.
The investigators stated that even if all engines had been working properly, the structural damage caused by the fuel leak and subsequent fire would still have caused the accident.
Even if the Pilot had aborted the takeoff, the investigators state that most likely the outcome would have still been catastrophic for the passengers, as the aircraft had exceeded its V1 speed.
The probable causes of the crash started with the high-speed impact of the tire with a foreign debris object on the runway, identified as a part of the thrust reverser engine from a Continental Airlines DC-10 that took off to Newark minutes earlier AF4590. The impact caused the destruction of the tire.
The strip of metal which had fallen from the engine of the DC-10 was not manufactured to specs. It had been the second strip of metal applied in a little more than a month. The part had been drilled too many times, and the metal strip was too large for the location.
A fragment of the destroyed tire impacted the lower part of the wing. However, instead of puncturing the fuel tank directly, the energy of the impact was transferred through the wing and fuel. A large portion of the fuel tank was ripped out of the wing, causing a massive fuel leak.
The igniting of the fuel compromised the structural integrity of the aircraft as well as caused the loss of thrust in engines two and one. BEA also states that the inability to retract the landing gear probably helped in keeping the fire burning. Under such conditions, the Flight Crew was unable to assess or fight the fire.
This accident and investigation also caused a number of recommendations that have changed things to this day.
While the Concorde itself never regained its glory and widespread use after the accident, the recommendations affect more than just Concorde.
The design of aircraft tires has drastically changed. Tires before this accident were known to be punctured, and Concorde itself had had 57 burst tires.
Twelve of these 57 burst tires had caused damage to the wings or tanks. Six of these 12 caused puncture of the fuel tanks and one actually had a piece of tire enter the fuel tank. Nineteen of the 57 were due to Foreign Object Debris. Twenty-one of the 57 had no detailed information.
The hazard of burst tires was already identified in June 1979, after a Paris-bound Air France Concorde made an emergency landing at Washington-Dulles after two tires burst on take-off, causing debris to rupture a fuel tank.
After the AF4590 investigation, the BEA and AAIB recommended the redesign of Concorde tires to make them safer in the case of a puncture.
The change of tires was not just for the Concorde, it had already been found on other aircraft. So the recommendation was made for all aircraft and is the beginning of the current aircraft tires we have today.
FOD and Maintenance
As Foreign Object Debris (FOD) was a cause of this accident, the BEA also recommended that aerodromes should add FOD sweeps into their normal operations.
With regards to the maintenance at Continental Airlines (CO), the BEA recommended that the FAA carry out an audit on all CO maintenance facilities worldwide.
Recommendations for Concorde
The recommendations regarding the fuel tanks were mainly that there needed to be an added liner to prevent the type of leak as seen in this accident. Beyond just for Concorde, the BEA recommended that more research be done on this type of fuel tank impact.
Beyond a design change to the fuel tanks, the BEA also recommended an update to the Operations Manual as well as to make changes to assist the flight crew in determining system status during events. An audit of Concorde operations and maintenance was also recommended, along with updated flight data recorders.
While the AAIB was involved in the investigation, they did make a number of notes at the end of the report. They noted that the French Judicial investigation, separate from the BEA investigation, impeded the AAIB’s investigation. They stated that access to the wreckage, evidence, and site was prevented, including to parts in which the United Kingdom had the primary airworthiness authority.
The BEA stated in response that while the AAIB might have had issues with access, the BEA themselves did not, so all information should be included in the report.
There were also other divergences between the BEA and the AAIB on the exact accident sequence and probable causes, which were reflected in the report. As the aircraft itself was completely destroyed, this is the reason that there are several causes reflected in the report for points such as fuel ignition.
There are two memorials for flight 4590, one near the airport and one at the crash site itself in Gonesse. At the crash site, there is a glass memorial marking the location where the 113 people lost their lives. In the center of the glass pane, there is also a portion of the aircraft.
The second memorial is located directly south of the Charles de Gaulle Airport. This memorial has several elements, with trees planted in the shape of Concorde, as well as a central memorial.
Along the pathway to the central memorial, there are stones engraved with the names of all of the victims. This memorial was inaugurated on the 5th anniversary of the accident.
Featured image: Aerospatiale-BAC Concorde 101, Air France. This permission only extends to photos taken by Michel Gilliand found at Wikimedia.