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The three worst airplane disasters in history

The three worst airplane disasters in history

9 Dec 2015 21:27:00

Although flying gets saver every year and airplane crashes are becoming more infrequent it sometimes, unfortunately, still happens. The worst airplane disasters happened a long time ago, all of them more than 20 years ago. That's saying something: flying is getting more save. Especially, considering that there are significantly more people flying and more airplanes in the air at any given time. 

Here is a warning though: if you have to fly in the next days better stop reading here. 

3. Charkhi Dadri mid-air collision

This is the deadliest mid-air collision in history between a Saudi Arabian Airlines Boeing 747 and a Russian made Ilushiun II-76 from Air Kazakhstan above the village Chardkhi Dadri in northern India. All people aboard both airplanes died, 312 on board the Saudi airplane and 37 on the Kazakh airplane. 

Although both captains were experienced aviators, both in their mid-fourties with over 9.000 flying hours, the crash was caused by the pilot of th Kazakhstan Airlines flight to follow the orders of the Air Traffic Control (ATC). Both were in the same flight path approaching each other. The Saudi Airplane was at 14.000 feet while the Kazakh airplane should have been at 15.000 feet. The investigation found that the crash was caused due to lack of English language skills and lack of flight instrumentations for the radio operator. The airplane was at first at 15.000 feet but it was slowly descending, unnoticed because the pilot was fighting turbulence in a cumulus cloud. The Kazakh airplane hit the Boeing on the left wing with its tail. Both planes went down severely damaged with no survivors.

2. Japan Airlines Flight 123

The disaster with JAL flight 123 is the deadliest singe-aircraft accident in history with the loss of 505 lives; only four people survived. The airplane, a Boeing 747SR was on route from Tokyo to Osaka. A short routine flight, the fifth flight that day for this airplane. Twelve minutes into the flight the rear bulkhead burst open leading to explosive decompression and the loss of the vertical stabiliser (the big vertical 'wing' at the back of the airplane). The rupture also damaged hydraulic lines and this combination led to an almost complete loss of control of the airplane. The pilots managed to keep the plane in the air for another 32 minutes before it crashed into a mountain side. 

The crash was caused by a faulty repair sever years earlier. The rear bulkhead was damaged at a tailstrike incident and the Boeing technicians used two seperate plates to repair it, while the procedure called for one plate to reinforce the bulkhead. The incorrect repair reduced the part's resistance to metal fatigue with about 70% and it was calculated later, it would lead to failure after about 10.000 pressurizations. The aircraft made 12.318 flights after this repair until it crashed.

1. Tenerife Airport Disaster

The deadliest aircraft disaster is the crash of two Boeing 747 (Pan-Am and KLM) on the runway of Los Rodeas Airport in Tenerife, one of the Canary Islands (in the Atlantic of the north African coast), killing 583 people aboard the two aircraft. Only 61 people survived, all people aboard the Pan AM airplane.

A bomb explosion at the Gran Canaria Airport led to the diversion of most airplanes to the much smaller Los Rodeas Airport which not only lacked parking space for so many aircraft, it also did not had ground radar. When a thick fog later developed the air traffic controllers could not see visibly nor by radar where all the aircraft were. The pilots of the two aircraft were also not able to see each other. The problem was that there were so many planes being diverted they had to park on the taxi way so leaving the runway to function as a taxi way as well. As a result of several misunderstandings the captain of the KLM flight decided to take off while the Pan Am flight was still on the runway. 

The misunderstanding leading to deaths of so many people was centered around the word 'take off' ;. The captain was ready to take off and waiting for the final go from the ATC. After they contacted the ATC with the message they were 'ready for take off' the captain believed he was cleared for take-off because the instructions from the ATC included the word take-off but it was only instructions for after take-off. The co-pilot readback of the ATC message completed it with 'we are now at takeoff' ;. Which he meant with 'at take-off position' ;, while the captain interpreted as 'beginning take-off'.

This whole miscommunication around one word between ATC and cockpit and within the cockpit led to a complete overhaul of communication instructions, which amongst others included to only use the word take-off for clearing and to use standardized phraseology only. 

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