Worst Aircrash Ever Klm into Pan Am Los Rodeos Airport (now Known As Tenerife North Airport)

In 1977 two Boeing 747 airliners collided on the runway of Los Rodeos Airport (now known as Tenerife North Airport) on the Spanish island of Tenerife, resulting in the deaths of 583 people, making it the worst accident in aviation history. The number of fatalities caused by airplane related crashes was exceeded only by the terrorist attacks on September 11, 2001.

The disaster took place on March 27, 1977 at 17:06:56 local time. The aircraft involved were the 747s of Pan Am Flight 1736 (the Clipper Victor) under the command of Captain Victor Grubbs, and KLM Flight 4805 (the Rijn) under the command of Captain Jacob Veldhuyzen van Zanten. Taking off on the only runway of the airport, the KLM flight crashed into the Pan Am aircraft taxiing in the opposite direction on the same runway.
Probable cause

While there is disagreement about their relative importance, the investigation concluded that the major factors of the accident were:

* KLM mistakenly took off without a take-off clearance.
* The sudden fog limited visibility greatly. The control tower and the crews of both planes were unable to see each other.
* Pan Am mistakenly continued to exit 4 instead of exiting at number 3 as directed by ATC.
* Simultaneous radio transmissions, with the result that neither message could be heard.
* Use of ambiguous non-standard phrases by the KLM co-pilot ("We're at take off") and the Tenerife control tower ("O.K.").
* The airport was (due to rerouting from the bomb threat) forced to accommodate a large number of large aircraft, resulting in disruption of the normal use of taxiways.

[edit] Speculations

Experts speculated about other contributing factors:

* Captain Veldhuyzen van Zanten's failure to confirm instructions from the tower. The flight was one of his first after spending six months training new pilots on a flight simulator. He may have suffered from 'training syndrome', having been in charge of everything at the simulator (including simulated ATC), and having been away from the real world of flying for extended periods.[2]
* The flight engineer's apparent hesitation to further challenge Veldhuyzen van Zanten, possibly because Captain van Zanten was not only senior in rank, but also one of the most able and experienced pilots working for the airline.[2]
* The possibility that van Zanten was in a hurry to commence the delayed flight due to Dutch regulations on exceeding crew duty hours.[10]
* The extra fuel that the KLM plane took on added several factors. It delayed take-off an extra 35 minutes, which gave time for the fog to settle in. It added 55 tons of weight to the plane, which made it more difficult to clear the Pan Am when taking off. It also made the explosion from the crash that ultimately killed everyone on board that much larger and more deadly.
* Captain van Zanten's reaction, once he spotted the Pan Am plane, was to attempt to take off before he had adequate airspeed. The sharp lifting angle caused the KLM jet to drag its tail on the runway, thereby reducing its speed even further. The plane had, however, exceeded its V1 speed[11].
* There was disagreement between the various investigative bodies, with the Dutch investigators suggesting that during the incident the Spanish control tower crew had been listening to a football game on the radio and that the American crew was at fault for staying on the runway. Both the Spanish and Pan American investigations pointed the finger primarily at the KLM crew