Tenerife airport disaster

On 27 March 1977, two Boeing 747 passenger jets collided on a runway at Los Rodeos Airport on the Spanish island of Tenerife, killing 583 people and injuring 61 others in the deadliest accident in aviation history.

The incident occurred at 17:06 GMT (UTC +0) in dense fog, when KLM Flight 4805 initiated its takeoff run, colliding with the right side of Pan Am Flight 1736, which was on the runway. The impact and the resulting fire killed all 248 people on board the KLM plane and 335 of the 396 people on board the Pan Am plane, with all 61 survivors being in the front section of the aircraft.

The two aircraft had landed at Los Rodeos earlier that Sunday and were among a number of aircraft diverted to Los Rodeos due to a bomb explosion at their intended destination of Gran Canaria Airport. Los Rodeos had become congested with parked planes blocking the only taxiway, forcing departing aircraft to taxi on the runway. Patches of thick fog were drifting across the airfield, so visibility was greatly reduced for pilots and the control tower.

An investigation by Spanish authorities concluded that the primary cause of the accident was the KLM captain's decision to take off believing that air traffic control (ATC) had issued takeoff clearance and that the Pan Am Boeing had cleared the runway, despite the latter radioing that they would "report when clear of the runway". Dutch investigators placed a greater emphasis on a mutual misunderstanding in radio communications between the KLM crew and ATC, but ultimately KLM admitted that its crew was responsible for the accident and the airline agreed to financially compensate the relatives of all of the victims.

The accident had a lasting influence on the industry, highlighting in particular the vital importance of using standard phraseology in radio communications. Cockpit procedures were also reviewed, contributing to the establishment of crew resource management as a fundamental part of airline pilots' training.