What happened to TWA Flight 800?

On 17 July 1996 at 20:31, just 11 minutes after take off,  the Boeing 747-131 TWA Flight 800 exploded and crashed over the Atlantic Ocean - the altitude was around 13,700ft.

All 18 crew and 212 passengers were tragically killed.

What caused the TWA Flight 800 explosion and crash?

The investigation’s reconstruction of the plane and experimental tests suggested the explosion was generated within the centre fuel tank. It was concluded that a kerosene vapour tank explosion had occurred in the near empty central tank, which ripped apart the aircraft’s structure and led to disintegration.

The aircraft also suffered some technical problems with sensors. During refuelling the volumetric shutoff (VSO) control was believed to have been triggered before the tanks were full. To continue the pressure fueling a mechanic overrode the automatic VSO by pulling the volumetric fuse and an overflow circuit breaker.

Maintenance records recorded this and, although the aircraft is recorded as taking off as normal, this does suggest mishandling during refuelling and management of the faulty indication equipment.

What can the industry learn from the TWA Flight 800 explosion and crash?

Fuel tank explosions can occur at sea level and at altitude - the key factors are the fuel volatility and the ambient fuel tank temperature. A major reason for the flammability of the fuel/air vapour was the large amount of heat generated and transferred to the center wing fuel tank (CWT) by air conditional packs located directly below the tank.

With the temperature raised to a sufficient level a single ignition source could cause an explosion. A plausible circumstance is that at the time of the explosion the CWT was empty , however sufficient fuel and vapour were present with a flashpoint of 44.4 - 47.2o C.

The fuel is said to have been heated by the added heat from the air conditioning packs to 46.1o C or higher - this coupled with ignition caused the event.