The Tenerife Airport Disaster

The Tenerife airport disaster occurred on March 27, 1977, when two Boeing 747 passenger aircraft collided on the runway of Los Rodeos Airport (now known as Tenerife North Airport) on the Spanish island of Tenerife, one of the Canary Islands. With a total of 583 fatalities, the crash is the deadliest accident in aviation history.

The aircraft involved, KLM Flight 4805 and Pan Am Flight 1736, were, along with many other aircraft, diverted to Tenerife from Gran Canaria Airport after a bomb exploded there. The threat of a second bomb forced the authorities to close the airport while a search was conducted. So many airplanes were diverted to the smaller Tenerife airport that controllers were forced to park many of them on the taxiway, thereby blocking it. Further complicating the situation, while waiting for authorities to reopen Gran Canaria, a dense fog developed at Tenerife, greatly reducing visibility. When Gran Canaria reopened, the parked aircraft blocking the taxiway at Tenerife required both 747s to taxi on the only runway in order to get in position for takeoff. Due to the fog, neither aircraft could see the other, nor could the controller in the tower see the runway or the two 747s on it. As the airport did not have ground radar, the only means for the controller to identify the location of each airplane was via voice reports over the radio. As a result of several misunderstandings in the ensuing communication, the KLM flight attempted to take off while the Pan Am flight was still on the runway. The resulting collision destroyed both aircraft, killing all 248 aboard the KLM flight and 335 out of 396 aboard the Pan Am flight. 61 people aboard the Pan Am flight, including the pilots and flight engineer, survived the disaster.[1]

As the accident occurred on Spanish territory, that nation was responsible for investigating the accident. Investigators from the Netherlands and the United States also participated. The investigation would reveal the primary cause of the accident was the captain of the KLM flight took off without clearance from Air Traffic Control.[1] The investigation would however specify that the captain did not intentionally take off without clearance, rather he fully believed he had clearance to take off due to misunderstandings between his flight crew and ATC.[1] Dutch investigators would place a greater emphasis on this than their American and Spanish counterparts,[2] but ultimately KLM would admit their crew was responsible for the accident, and the airline financially compensated the victims.