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. The captain is no longer considered infallible, and combined crew input is encouraged during aircraft operations.

Background

Tenerife was an unscheduled stop for both flights. Their destination was Gran Canaria Airport (also known as Las Palmas Airport or Gando Airport), serving Las Palmas on the nearby island of Gran Canaria.

Collision

According to the cockpit voice recorder (CVR), the Pan Am captain said, "There he is!" when he spotted the KLM's landing lights through the fog just as his plane approached exit C4. When it became clear that the KLM aircraft was approaching at takeoff speed, Captain Grubbs exclaimed, "Goddamn, that son of a bitch is coming!", while first officer Robert Bragg yelled, "Get off! Get off! Get off!" Grubbs applied full power to the throttles and made a sharp left turn toward the grass in an attempt to avoid the impending collision.

By the time the KLM pilots saw the Pan Am aircraft, they had already exceeded their V1 speed and were moving too fast to stop. In desperation, the pilots prematurely rotated the aircraft nose upward and attempted to clear the Pan Am by lifting off, causing a 22 m tailstrike. The KLM 747 was within 100 m of the Pan Am and moving at approximately 140 knot when it left the ground. The KLM 747's nose landing gear cleared the Pan Am, but its left-side engines, lower fuselage, and main landing gear struck the upper right side of the Pan Am's fuselage, ripping apart the middle of the Pan Am jet almost directly above the wing. The KLM 747's right-side engines crashed through the Pan Am's upper deck immediately aft of the cockpit, instantly killing all of the passengers seated there.

The KLM plane remained briefly airborne, but the impact had sheared off the No. 1 engine (outer left), caused significant amounts of shredded materials to be ingested by the No. 2 engine (inner left), and damaged the wings. The plane immediately went into a stall, rolled sharply, and hit the ground approximately 150 m past the collision, sliding down the runway for a further 300 m. Upon impact with the runway, the full load of fuel ignited into a fireball that could not be subdued for several hours. One of the 61 survivors of the Pan Am flight said that sitting in the nose of the plane probably saved his life: "We all settled back, and the next thing an explosion took place and the whole port side, left side of the plane, was just torn wide open."

Veldhuyzen van Zanten was KLM's chief of flight training and one of their most senior pilots. About two months before the accident, he had conducted the Boeing 747 qualification check on the first officer of Flight 4805. His photograph was used for publicity materials such as magazine advertisements, including the inflight magazine on board PH-BUF. KLM had suggested initially that Veldhuyzen van Zanten should help with the investigation, unaware that he was the captain who had been killed in the accident.