Tenerife, March 27 1977

The Crash
Sunday March 27, 1977 started like any other normal day on the island of Tenerife. Then at 1:15pm, and explosion ripped through the passenger terminal at Las Palamas International Airport. No one was killed as there was a warning beforehand. However, another warning was received of another device in the building. The decision was made therefore to close the airport.

At the time of the explosion, KLM flight KL4805, a charter 747(registration PH-BUF) for the Holland International Travel Group was flying towards Las Palamas, with 234 passengers on board, including 3 babies, and 48 children. Most of the passengers were Dutch, but there were 2 Australians, 4 Germans, and 2 Americans on the flight. The captain on this flight was KLMs most famous pilot, Captain Jacob Veldhuyzen van Zanten. He had been flying since 1947, with KLM since 1951, and had 1500 hours in the 747. He spent most of his time in simulators training other pilots. He had a total of 12,000 hours experience.

KL4805 diverted to Tenerife, and landed at Los Rodeos Airport, at 110pm local time. Upon landing they were greeted with a low cloud cover, light rain, and fog. KL4805 was directed to exit the runway at the last taxiway, and park on an apron area, next to several other aircraft.

Approximately 30 minutes later, Pan American flight 1736 (Clipper Victor the first 747 to fly passengers, registration N736PA) with 378 passengers on board landed and parked behind KL4805. The flight had originated in Los Angeles but was an hour and a half late, with 380 passengers on board, and flew to New York, where it refueled, added 14 passengers and changed crews. They were on the ground for about 90 minutes before departing for Gran Canaria. Most of the passengers were of retirement age, traveling to meed a cruise ship for a 12 day cruise.

The PanAm crew was impatient to get going again, as they had been on duty for 8 hours already, and most of the passengers had been on the plane for 13 hours already. The crew asked to be put into a holding pattern, as they had enough fuel to loiter for awhile, but the requests were denied, and they landed on Tenerife.

Captain van Zanten, concerned about crew rest, and being prosecuted for flying over hours, made the request that the plane be refueled for the return flight while on Tenerife. This required fuel trucks driving out to the plane, and refueling it while parked on the taxiway. This was a slow process, as they didn't have underground fuel pits that could be used there.

After being on the ground several hours, Las Palamas reopened. PA1736 requested clearance to taxi to the runway, but were blocked in by several aircraft, including KL4805. The crew got out and measured the distance to the back of the KLM 747, and realized they would have to wait for them to taxi before they could depart.

Just before 5pm KL4805 requested taxi clearance. By this time the fog had gotten thicker, and visibility was down to about 300 meters. KL4805 was cleared to back taxi down runway 30, initially being instructed to turn off at the 3rd taxiway, back tracking down runway 12 to the departure end of runway 30. This was amended to going to the end of runway 30 and making a 180. Meanwhile, PA1736 was going down the same runway, with instructions to turn off at the 3rd taxiway. There was some confusion in the cockpit of the PanAm flight as to whether the tower controller said 3rd or 1st, but when they tried to radio for clarification, the KLM was using the radio, and the transmissions went over each other. At this point the fog was so thick the tower couldn't see either plane.

PanAm concluded that the 4th taxiway was the third, because the third was a 135 degree turn, which would have been very tight for a 747. They continued towards the 4th taxiway, which was a 45 degree angle to the runway, while KL4805 completed its turn at the end of the runway. Captain van Zanten advanced the throttles and began to take off, when the first officer yelled they weren't cleared to take off yet. The Captain ordered him to call and get clearance, at which time they received ATC clearance for AFTER take off. They were ordered to wait for take off clearance, but van Zanten released the brakes and began to take off while the copilot was reading back the clearance.

ATC radioed to the plane "OK. Standby for takeoff, I will call you." Unfortunately at the same time, PA1736 radioed "We are still taxiing down the runway!" Both transmissions walked over each other and all that was heard on the KLM was "OK". Twenty seconds into takeoff, the flight engineer heard another exchange between ATC and PA736.

ATC: Roger Pan Am 1736. Report clear of the runway.
Pan Am: Ok. Will report when we are clear.

The flight engineer asked the pilots "Is he not clear of the runway?" to which van Zanten replied "Oh yes." Shortly after this, Pan Am 1736 realized that the KLM 747 was rolling down the runway, and tried to get clear. The aircraft turned sideways and throttled up, desperately trying to get clear of the runway. KL4805, when they realized that the other 747 was still on the runway, desperately tried to get airborne and go over the Pan Am flight, leaving a 3 foot deep gouge in the runway. At approximately 5:06pm local time, KL4805 impacts PA1736 just behind the upper deck. KL4805 climbed to approximately 500 feet before slamming back into the runway, exploding and killing all 248 people on board. Most of the passengers on the side of the Pan Am flight were killed instantly in the impact. Many others were killed in the subsequent fire. Of the 396 people on board 335 were killed.

The Investigation
The crash happened on Spanish territory, but due to the horrifying death toll, the Dutch and Americans insisted on sending their own investigators as well as the Spanish investigators. The Dutch originally tried to contact Van Zanten to lead their team, not realizing that he was the pilot of the accident aircraft. A total of 60 investigators arrived at the scene to investigate.

The American investigators concluded that the Dutch crew was at fault. One of the conclusions was that Captain Van Zanten was held in such high esteem that the copilot didn't question the decision to take off even though it was unclear whether the Pan Am flight had left the runway. Captain Van Zanten was held to be almost solely responsible for the accident, by making the decision to take off, even though they didn't know if the runway was clear, or verifying take off clearance. The Dutch copilot added to their readback, "We are now at take off", meaning that they were taking off, but even the investigators failed to understand that this meant they were rolling down the runway.

The Dutch government refused to accept this explanation, and blame the Pan Am crew completely for the accident, saying that they failed to follow ATC instructions and turn off at the third taxiway, instead thinking that it was the 4th that was meant. Both reports partially blame the controllers, saying that the crews had a hard time understanding their instructions.

There were rumors that the controllers were in the tower listening to a football game during the accident, but there was no evidence that anything was going on, except overwhelmed controllers, that weren't used to handling aircraft of this size, or of the number handled on that day.

Conspiracy?
After the American report was issued, the Dutch government refused to accept it, and did everything they could to counter it by showing what experience the KLM pilot had, and how famous he was. The Dutch government did everything they could to shift the blame solely to the crew of PA1736, and exonerate their crew/pilot. ATC tapes, and the CVR clearly show that the flight was NOT cleared to take off, but the KLM pilot began the take off roll anyway. It is believed that the pressure of the crew's remaining hours, having to fly home from Las Palamas within that time, and the comfort of the passengers led to Van Zanten not having his mind completely on flying the aircraft, and following procedures.