27 March 1977 Tenerife Airport Disaster
The Tenerife airport disaster occurred on Sunday, March 27, 1977, when two Boeing 747 passenger aircraft collided on the runway of LosRodeos Airport (now known as Tenerife North Airport) on the Spanish island of Tenerife. With 583 fatalities, the crash is the deadliest accident in aviation history.
After a bomb exploded at GranCanariaAirport, many aircraft were diverted to Tenerife. Among them were KLM Flight 4805 and Pan Am Flight 1736 – the two aircraft involved in the accident. Due to the numbers involved, air traffic controllers were forced to park many of the aircraft on the taxiway, thereby blocking it. To make matters worse, a dense fog developed at Tenerife, greatly reducing visibility.
When Gran Canaria reopened, the parked aircraft blocking the taxiway at Tenerife required both of the 747’s to taxi on the only runway in order to get in position for takeoff. Unfortunately, the fog was so thick that neither aircraft could see the other, nor could the controller in the tower see the runway or the two 747’s on it. As the airport did not have ground radar, the only means for the controller to identify the location of each aircraft was via voice reports over the radio. As a result of several misunderstandings in the communications, 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 of 396 aboard the Pan Am flight.