Aviation Accidents

Illustrations for “What Went Wrong–Twenty Years of Airline Accidents (1996-2015)” by Graham Deighton [Austin Macauley Publishers].

Trans World Airlines Flight 800, July 1996.

Trans World Airlines Flight 800 (TWA800) was a Boeing 747-100 that exploded and crashed into the Atlantic Ocean near East Moriches, New York, on July 17, 1996, at about 8:31 pm. EDT, 12 minutes after takeoff from John F. Kennedy International Airport, on a scheduled international passenger flight to Rome, with a stopover in Paris. All 230 people on board died in the crash; it is the third-deadliest aviation accident in U.S. history.

Map showing the flight path, coloured rectangles indicate areas where wreckage was found.

Boeing 747-100 with colour coded sections corresponding to the debris fields.

The four-year NTSB investigation concluded with the approval of the Aircraft Accident Report on August 23, 2000, ending the most extensive, complex, and costly air disaster investigation in U.S. history at that time.

The report’s conclusion was that the probable cause of the accident was explosion of flammable fuel vapours in the centre fuel tank. Although it could not be determined with certainty, the likely ignition source was a short circuit.

Problems with the aircraft’s wiring were found, including evidence of arcing in the fuel quantity indication system (FQIS) wiring that enters the tank. The FQIS on Flight 800 is known to have been malfunctioning; the captain remarked on “crazy” readings from the system about 2 minutes and 30 seconds before the aircraft exploded. As a result of the investigation, new requirements were developed for aircraft to prevent future fuel tank explosions.

Boeing 747-100 showing the wing centre section and fuel tank.

Swissair Flight 111, September 1998

Swissair Flight 111 was a scheduled international passenger flight from John F. Kennedy International Airport in New York City, United States, to Cointrin Airport in Geneva, Switzerland. On 2 September 1998, the McDonnell Douglas MD-11 performing this flight, registration HB-IWF, crashed into the Atlantic Ocean southwest of Halifax Stanfield International Airport at the entrance to St. Margarets Bay, Nova Scotia.

The crash site was 8 kilometers from shore, all 229 passengers and crew on board the MD-11 were killed, making the crash the deadliest McDonnell Douglas MD-11 accident in aviation history. Le Peintre (The Painter) by Pablo Picasso, was also on board the aircraft and was destroyed in the accident.

The flight path of Flight 111

The search and rescue response, crash recovery operation, and investigation by the Government of Canada took more than four years and cost CA$57 million. The investigation carried out by the Transportation Safety Board of Canada (TSB) concluded that flammable material used in the aircraft’s structure allowed a fire to spread beyond the control of the crew, resulting in the crash of the aircraft. Several wide-ranging recommendations were made which have been incorporated into new US Federal Aviation Administration standards.

A conversation recorded by the Cockpit Voice Recorder (CVR) indicates that there was visible smoke in the cockpit and it was suggested that the problem might lie with the air conditioning. However, a flight attendant summoned to the cockpit said that there was no smoke or unusual smell in the passenger compartment. The crew requested a diversion to Boston airport, but accepted an offer to land at the nearer Halifax Airport.

The pilot and co-pilot soon donned their oxygen masks and, in accordance with the Swissair checklist “In case of smoke of unknown origin”, the crew shut off power to the cabin, which also turned off the recirculating fans in the cabin’s ceiling. This allowed the fire to spread to the cockpit, eventually shutting off power to the aircraft’s autopilot. At 22:24:28 AT (01:24:28 UTC), the crew informed Halifax that “we now must fly manually”, followed by declaring an emergency. Ten seconds later, the crew declared an emergency again, saying “…and we are declaring emergency now, Swissair one eleven”; this was the last transmission received from Flight 111.

The MD-11 cockpit attic area and forward cabin drop ceiling area, where the fire originated.

Investigators found evidence of arcing in wiring of the In-Flight Entertainment Network (IFEN) System which allowed passengers to select in-flight movies, audio channels and other features. As a “non-essential” system it had been installed directly to the aircraft’s power supply and was not deactivated when the crew switched off the CABIN BUS switch.

IFEN wiring installation.

Cockpit Overhead Diffuser Outlet and Avionics Circuit Breaker Panels.

The rapid spread of electrical power failures led to the breakdown of key avionics systems, and the crew was soon rendered unable to control the aircraft. The pilot-in-command was forced to fly manually because he had no light by which to see his controls after the instrument lighting failed. The fuel-laden plane was above maximum landing weight so the flight crew activated dumping of fuel. The pilots lost all control and the doomed plane flew into the ocean un-commanded. Recovered fragments of the plane show that the temperature inside the cockpit became so great that aluminium parts in the flight deck ceiling had melted.

Egypt Air Flight 990, October 1999.

Egypt Air Flight 990 was a regularly scheduled flight from Los Angeles International Airport to Cairo International Airport, with a stop at John F. Kennedy International Airport, New York City. On October 31, 1999, the Boeing 767-300ER operating the route crashed into the Atlantic Ocean about 60 miles (100 km) south of Nantucket Island, Massachusetts, killing all 217 passengers and crew on board.

The flight path of Flight 990.

Since the crash occurred in international waters, it was investigated by the Ministry of Civil Aviation’s Egyptian Civil Aviation Agency (ECAA) and the National Transportation Safety Board (NTSB) under International Civil Aviation Organization rules. As the ECAA lacked the resources of the NTSB, the Egyptian government asked the American government to have the NTSB handle the investigation. Two weeks after the crash, the NTSB proposed handing the investigation over to the Federal Bureau of Investigation, as the evidence they had collected suggested that a criminal act had taken place, and that the crash was intentional rather than accidental. The Egyptian authorities refused to accept the proposal to hand the investigation over to the FBI, so the NTSB was forced to continue the investigation alone, despite it falling outside of their investigative purview.

The cockpit voice recorder (CVR) recorded the captain excusing himself to go to the lavatory, followed 30 seconds later by the first officer saying in Egyptian Arabic “Tawkalt ala Allah,” which can be translated as “I put my trust in God.” A minute later, the autopilot was disengaged, immediately followed by the first officer again repeating the same Arabic phrase which can be also translated as, “I rely on God.” Three seconds later, the throttles for both engines were reduced to idle, and both elevators were moved 3° nose down. The first officer repeated “I rely on God” seven more times before the captain, who had returned to the cockpit, suddenly asked repeatedly, “What’s happening, what’s happening?”

The flight data recorder (FDR) reflected that the elevators then moved into a split condition, with the left elevator up and the right elevator down, a condition that is expected to result when the two control columns are subjected to at least 50 pounds-force (220 newtons) of opposing force. At this point, both engines were shut down by moving the start levers from run to cutoff. The captain asked, “What is this? What is this? Did you shut the engines?” The captain is then recorded as saying, “get away in the engines” (this is the literal translation that appears in the NTSB transcript), followed by “shut the engines”. The first officer replies “It’s shut”. The final recorded words are the captain repeatedly stating, “Pull with me” but the FDR data indicated that the elevator surfaces remained in a split condition (with the left surface commanding nose up and the right surface commanding nose down) until the FDR and CVR stopped recording.

No other aircraft were in the area, and no indication was given that an explosion occurred on board. The engines operated normally for the entire flight until they were shut down. From the presence of a western debris field about 1,200 ft (370 m) from the eastern debris field, the NTSB concluded that the left engine and some small pieces of wreckage separated from the aircraft before water impact.

The Boeing 767 elevator system has two parallel sets of flight control components which can work independently and in opposition to each other because of an override mechanism at the control columns and aft quadrant.

The NTSB found that the probable cause of the accident was the airplane’s departure from normal cruise flight and subsequent impact with the Atlantic Ocean “as a result of the first officer’s flight control inputs”, but did not determine a specific reason for the first officer’s alleged actions.

The Egyptian authorities rejected this conclusion, as the suggestion of murder/suicide was offensive to their culture and religion, and concluded that the incident was caused by mechanical failure of the aircraft’s elevator control system. Their report suggested several possibilities for the cause of the accident, focusing on the possible failure of one of the right elevator’s power control units. However, the NTSB dismissed the ECAA report after it was found that no scenario could explain the doomed flight’s final movements other than an intentional human act.

Investigators found no mechanical failure in the Boeing 767 elevator system that could have resulted in a split condition.

The loss of Egypt Air 990 remains highly contentious.

Air France Concorde Flight 4590, July 2000

Air France Flight 4590 was an international charter flight of Air France, from Charles de Gaulle Airport, Paris, to John F. Kennedy International Airport, New York, flown by an Aérospatiale-BAC Concorde. On the afternoon of Tuesday, 25 July 2000, at 16:44:31 local time (UTC 14:44:31), the aircraft serving the flight (registration F-BTSC) ran over debris on the runway during takeoff, blowing a tyre, which threw chunks of tyre into the underside of the left wing and into the landing gear bay with great force.

The fuel tank built inside the left wing was full, with almost no ullage. When the tyre fragments struck the wing, the tank ruptured, thereby releasing large quantities of fuel. Tyre fragments severed wiring in the landing gear bay, preventing retraction of the landing gear. Fuel from the ruptured tank ignited, causing a loss of thrust in engines 1 and 2. Lack of thrust, high drag from the extended landing gear, and fire damage to the flight controls made it impossible to control the aircraft, which crashed into a hotel in nearby Gonesse two minutes after takeoff. All 109 people on board were killed, alongside four in the hotel. Six other people in the hotel were critically injured.

It was the only fatal Concorde accident during its 27-year operational history.

American Airlines Flight 587, November 2001.

American Airlines Flight 587 was a regularly scheduled international passenger flight from John F. Kennedy International Airport to Las Américas International Airport in Santo Domingo, the capital of the Dominican Republic. On November 12, 2001, the Airbus A300B4-605R flying the route, crashed into the neighbourhood of Belle Harbor, on the Rockaway Peninsula of Queens, New York City, shortly after takeoff.

All 260 people aboard the plane (251 passengers and 9 crew members) were killed, along with five people on the ground. It is the second-deadliest aviation accident in U.S. history behind the crash of American Airlines Flight 191 in 1979, and the second-deadliest aviation incident involving an Airbus A300.

The flight path of Flight 587.

The aircraft taxied to Runway 31L behind a Japan Airlines (JAL) Boeing 747-400 (JAL Flight 47) preparing for takeoff. The JAL flight was cleared for takeoff at 9:11:08 am EST. At 9:11:36, the tower controller cautioned Flight 587 about potential wake turbulence from the preceding Boeing 747.

American Airlines incorrectly taught pilots to use the rudder for wake turbulence recovery, resulting in the first officer’s possible misunderstanding of the aircraft’s response to full rudder at high airspeeds. American Airlines’ Advanced Aircraft Maneuvering Program (AAMP) tended to exaggerate the effects of wake turbulence on large aircraft, creating a simulation scenario whereby turbulence from a 747 creates a 90° roll (rather than the likely 5 to 10° roll, though not explaining this to the pilots) to maximise the training challenge. Therefore, pilots were being inadvertently trained to react more aggressively than was necessary.

Consequently, the First Officer (who was the pilot flying) alternated between moving the rudder from the right to the left and back again in quick succession causing sideslip until the lateral force caused composite lugs that attached the vertical stabiliser to fail. The stabiliser separated from the aircraft and fell into Jamaica Bay, about 1 mile (1.6 km) north of the main wreckage site.

The aircraft pitched downwards after the stabiliser loss. As the pilots struggled to control the aircraft, it went into a flat spin. The resulting aerodynamic loads sheared both engines from the aircraft; they fell several blocks north and east of the main wreckage site, causing minor damage to a gas station and major damage to one home and a boat. The loss of engines cut power to the Flight Data Recorder (FDR), while the cockpit voice recorder (CVR), using an emergency bus, cut off on impact with the ground. At 9:16:04, the stall warning sounded on the CVR. The last recorded words were the First Officer saying, “What the hell are we into, we’re stuck in it” (9:16:07) with the Captain replying, “Get out of it, get out of it.”.The aircraft slammed into the ground at Newport Avenue and Beach 131st Street.

Attachment of the vertical stabiliser to the aft fuselage.

Each of the six attachment points has two sets of attachment lugs, one made of composite material, another of aluminium, all connected by a titanium bolt; damage analysis showed that the bolts and aluminium lugs were intact, but not the composite lugs.

The possibility that the composite materials might not be as strong as previously supposed was a cause of concern, as they are used in other areas of the plane, including the engine mounting and the wings. Tests carried out on the vertical stabilisers from the accident aircraft, and from another similar aircraft, found that the strength of the composite material had not been compromised, and the NTSB concluded that the material had failed because it had been stressed beyond its design limit.