Tenerife airport disaster

The Tenerife disaster took place on March 27, 1977, when two Boeing 747s collided on the island of Tenerife, killing 583. The Tenerife disaster had the greastest number of casualties of any air disaster until the September 11, 2001 Terrorist Attacks.

On March 27, 1977 a Pan American Boeing 747 had taken off from New York's JFK International Airport, bound for the tropical Canary Islands. Upon approaching its final destination Las Palmas it was told the major airport was temporarily closed due to a bomb alert and was ordered to divert to a smaller airport at the neighbouring island Tenerife, together with many other planes. The small airport at Tenerife was not equipped for large planes, let alone so many. Platform space was insufficient, delays were inevitable. Tension and confusion arose.

When Las Palmas was reopened planes prepared to continue their journey, including the PanAm Boeing. Meanwhile a similar KLM 747, flying as a charter full with vacationers, was getting ready to head back to Amsterdam. KLM had instructions to depart first, PanAm would follow. Soon after, the KLM jet began taxiing to the end of the main runway, and once it got there it got into holding position, waiting for the approval to take off.

What happened next would turn out to be a fatal chain of events:

With KLM ready to go, PanAm was instructed to taxi along the same main runway until they reached exit 2, then to head further to the take off point via a parallel road. Due to the heavy fog they more or less missed exit 2, which involved a sharp turn backwards anyway, so they decided to go on till exit 3, which was heading in the right direction.

The control tower gave the KLM plane instructions to hold, however, the KLM plane mistakenly thought they had heard the tower grant them permission to take off. Since there was dense fog, the KLM's pilots were unable to see the PanAm 747 that was right in front of them.

Later investigation showed that the KLM pilots misinterpreted some of Tenerife's instructions. This was partly caused by missed radio messages (calls from both planes to the tower and vice versa cancelled each other), partly by non standard phrases used by the tower, partly by the Dutch first pilot seemingly jumping to conclusions (which later was hard to accept for the investigators, the pilot was otherwise known as a first class pilot).

KLM's first pilot released the brakes, thinking that they had permission to take off. In fact the copilot uttered some hesitations about the level of clearance they had obtained, but he was immediately overruled and hesitated to further challenge the first pilot, who was not only senior in rank but also one of the most able and experienced pilots of the company.

The Tenerife tower watched helplessly and in horror as the KLM plane hurtled towards the PanAm plane at full take-off speed.

As soon as PanAm, still taxiing along, spotted the KLM 747, the pilots tried to take a sharp turn away from the runway, but the collision was only seconds away. The KLM plane, by now already partially free from the ground slammed the PanAm plane on the side, and part of the fuselage of the Pan Am jet was ripped apart. The KLM plane twisted around and ended up near the PanAm jet. All 234 passengers and 14 crew members in the KLM plane were killed, and 321 of the 380 aboard the PanAm flight perished too. The PanAm first pilot was among the survivors.

As a consequence of the accident, many regulations and airplane specifications came about in the whole airline industry. It was made a worldwide rule that all control towers and pilot crews had to use English standard phrases. Airplane manufacturers began implanting equpiment that helped planes see thru fog. Cockpit procedures were also changed. Hierarchical relations were played down. More emphasis was placed on decision taking by mutual agreement.

Both airlines as a whole were never blamed for faulty procedures or otherwise. KLM's safety records were excellent and have been so ever since. PanAm was a top quality airline as well. Of course many years later a terrorist bomb attack over Lockerbie would mean its undeserved demise.

The tragedy of March 27, 1977 was known, for many years, as the world's largest aviation tragedy, until a Kazakhstan Airlines Il-76 and a Saudi Arabian Airlines 747 crashed over Mumbai in 1996. Until then, it was known as the airplane collision with the largest number of casualties.

More information can be found at aviation.com, where a transcript of the conversation in both planes can also be found.