Three worst-ever aviation accidents in human history

The KLM Royal Dutch Airlines plane collision with a Pan Am aircraft in 1977 happens to be the worst-ever aviation accident in history, as it had resulted in 583 fatalities, research shows.

Deadly crossroads in Spain: On March 27, 1977 (Sunday), a KLM Royal Dutch Airlines plane (Flight Number KL4805) had collided with a Pan Am aircraft (Flight 1736) on the runway at Los Rodeos Airport (now Tenerife North Airport on Spain’s Canary Islands, resulting in 583 fatalities, according to the US Federal Aviation Administration, the Aviation Safety Network, the Tenerife Airport Information Centre, the Global Operators Fight Information Resource and the Pan Am Historical Foundation etc.

While the number of fatalities on the KLM plane was 248 (234 passengers and 14 crew members), no fewer than 335 humans (326 passengers and nine crew members) aboard the Pan Am plane had lost lives.

While 61 people aboard the Pan Am aircraft had sustained injuries, an equal of people had managed to survive. A bomb explosion at Spain’s Gran Canaria airport and the threat of a second bomb had caused many aircraft to be diverted to Los Rodeos Airport. Among them were KLM Flight 4805 and Pan Am Flight 1736 – the two aircraft involved in the accident.

At Los Rodeos Airport, air traffic controllers were forced to park many of the airplanes on the taxiway, thereby blocking it. Further complicating the situation, while authorities waited to reopen Gran Canaria, 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 747s to taxi on the only runway in order to get in position for takeoff. The fog was so thick that neither aircraft could be seen from the other, and the controller in the tower could not see the runway or the two 747s on it. As the airport did not have ground radar, the controller could find where each airplane was only by voice reports over the radio.

The investigations revealed that the primary cause of the accident was the captain of the KLM flight taking off without clearance from Air Traffic Control. The investigation specified that the captain did not intentionally take off without clearance; rather he fully believed he had clearance to take off due to misunderstandings between his flight crew and ATC.

Dutch investigators placed a greater emphasis on this than their American and Spanish counterparts, but ultimately KLM admitted their crew was responsible for the accident, and the airline financially compensated the victims' relatives.

Less experienced flight crew members were encouraged to challenge their captains when they believed something was not correct, and captains were instructed to listen to their crew and evaluate all decisions in light of crew concerns.

Crash of Japan Airlines Flight in 1985: The crash of Japan Airlines Flight 123 on August 12, 1985, is the single-aircraft disaster with the highest number of fatalities. Some 520 people had perishes aboard a Boeing 747 after the aircraft had suffered an explosive decompression from an incorrectly repaired aircraft part, which had ultimately failed in mid flight.

Pilots were able to keep the plane flying for 32 minutes after the mechanical failure before crashing into a mountain. All 15 crew members and 505 of the 509 passengers on board died. The death toll was exacerbated by delays in the rescue operation. Although a number of people survived, by the time the Japanese rescue teams arrived at the crash site all but four had succumbed to their injuries.

The 1996 mid-air collision involving Saudi and Kazakh planes over Haryana: On November 12, 1996, the world's deadliest mid-air collision had involved a Saudi Airlines flight 763 and a Kazakhstan Airlines Flight 1907 over Haryana in India. The collision was mainly the result of the Kazakh pilot flying lower than the assigned clearance altitude. All 349 passengers and crew on board both aircraft died.

The Indian Ramesh Chandra Lahoti Commission, empowered to study the causes, had recommended the creation of "air corridors" to prevent aircraft from flying in opposite directions at the same altitude.

The Civil Aviation Authorities in India had thus made it mandatory for all aircraft flying in and out of India to be equipped with a Traffic Collision Avoidance System, hence setting a worldwide precedent for mandatory use of this system.