Tenerife Disaster Communication Errors
This unfortunate disaster occurred on the 27th March 1979. Two Boeing 747's collided on the runway at Los Rodeos airport during taxi and take-off procedures during low visibility conditions caused by a fog.
KLM4805 and Pan Am 1736 had been diverted to Los Rodeos airport a few hours earlier due to a bomb exploding at Gran Canaria airport. The bomb had been set off by the movement for independence and autonomy of the Canaries archipelago. The bomb ironically did not hurt anyone, however no one could imagine its downstream effects that day.
Los Rodeos is not a large airport and is not normally accustomed to dealing with Boeing 747 aircraft, let alone two. To Fit them and the other aircraft diverted there the ground controllers had fit aircraft in certain areas, unfortunately KLM4805 parked blocking Pan AM 1736. However this seemed the least of the problems as no aircraft would be departing until the mess at Gran Canaria airport had been cleaned up.
At 1651 GMT KLM 4805 finally received its start clearance. Due to aircraft being parked blocking the normal taxi way they were instructed to backtrack runway 30. Shortly after Pan Am 1736 were also given their taxi clearance, also to backtrack and exit using the third taxiway. At this time weather in the vicinity of Los Rodeos airport had also deteriorated and visibility had decreased to 100 to 200 meters. This decrease in visibility led to some confusion on the flight deck of the Pan Am aircraft.
By this time KLM 4805 had completed its back track and upon completing the 180 degree turn, Captain Van Zantan immediately began the take-off. However the first officer interjected they were not cleared and requested the airways clearance which was received from the tower. The clearance also contained the word 'takeoff'. Upon reading back the clearance the captain assumed they were cleared for takeoff and began the take-off roll. However the first officer although surprised made a radio call "we are at take off". Although the First officer did not say so he was sufficiently concerned.
Upon hearing this call in the Pan Am aircraft they realized KLM had begun their take-off roll and immediately tried to intervene by saying they were still on the runway, unfortunately by chance the controller also realized and made a radio call at the same time. All that was heard in the KLM cockpit was a sequel although both air traffic control and Pan Am would of assumed their radio calls were received by KLM.
A short time later KLM collided with the Pan Am aircraft with catastrophic consequences.
583 people were killed making it the largest single aviation disaster to date.
|(Video embedded from YouTube on 30 August 2012-)|
The Communication errors caused by the two transmissions together are called a hetrodyne. This is heard to others on the radio a a sequel or garbled transmission and still exisit today. There is technology available to overcome this problem however few airlines and aircraft manufacturers have adopted it. The two transmissions together were bad luck however in this case there were other communication errors.
Air traffic control had no standard phraseology. What does this mean? Currently the only time an aircraft will be issued with the instruction 'take-off' will be for a take-off clearance. In 1979 often standard route clearances (the route the aircraft is cleared to fly) would be issued with phraseology such as 'take-off'. for example "after take-off climb the 329 radial then direct to Palmerston North". This could no longer happen in the standard phraseology environment we now operate within.
In both cases the Captain of the KLM aircraft assumed that the "take-off" phraseology meant he was cleared for take-off.
Inter cockpit communication errors also existed. Initially the first officer on board the KLM flight stopped Captain Van Zantan from commencing the take-off. However the second time he did not and whilst the Airline Pilots association accident report made comment that the first officer was clearly uncomfortable he did not speak up. Why? Was it that he had simply failed to convey this information to the Captain or had he felt uncomfortable bringing it to the attention of the Captain? unfortunately that will never be know.
The prime reason for communication is the conveyance of knowledge, behavior and skills.
In the above accident it is clear that the break down in communication led to a critical mistake, the take-off roll continuing, simply had the take-off been aborted the disaster would of been averted.
How did the First officer communicate? We are only privileged to the cockpit voice recorder (CVR) which really only shows what it said, or in this case not said. However communication is that much more than just speech. It is often said that 80% of communication is visual.
How else do we communicate?
- Symbols, signs and signals
- Personal appearance
- Sounds and music
- Spoken words
- Tone and volume
- Body language
Captain and First officer Communication
In this accident the Captains decision to continue the take-off was flawed in hindsight. The first officers ineffectiveness to assert himself to get that information across to the captain to abort the take-off ultimately led to the death off 583 people.
The captain has two primary roles
- To be in complete command of the situation
- To be in complete control of the aircraft
To do this the captain must process a huge amount of information to make the correct decision, it is not possible that the captain could possibly have all the information for every situation. Here the First officers role comes to play, he must be able to offer information as well as alternatives. However the job of doing this can be somewhat more complicated that first seen. The interaction is not only controlled by the pilots rank and role but also their personality.
In this case why did the First officer not assert himself greater on the Captain.
Captain Van Zantan was a senior check and training Captain at KLM and was considered with great dignity and respect. It may of been this which made it hard for the First Officer to speak up twice, note he did speak up the first time however was unable to the second. The report was clear that the Captain was ready to go and was somewhat rushed by flight and duty limits, essentially commercial pressure to get the job done.
The Captain was also quite un-current on line operations as he spent most of his time in the simulator. He lack of route experience and exposure to a complicated environmental situation was exasperated by not slowing down.
A breakdown in communication generally occurs when one person in the flight crew takes the position of non-negotiation. When one crew member makes it clear that they are making decisions and not listening then there is no hope of constructive communications which is essential to safe aviation.
Similarly a crew member that is too eager to please and goes along with everything said by the other crew member is also equally destructive to communications.
Essential communications requires good listening, and good listening is not as simple as sitting quietly. A good listener, actively listens. They do not interrupt but pause, ask questions and re-afirm what has been said. They will also use good body language and gestures.
:1: Airline Pilots Association. (n.d.). Aircraft Accident Report. Washington, D.C.: Engineering and Air Safety. Retrieved from www.project-tenerife.com
:2: Robson, D. (2008). Human being pilot : Human factors for aviation professionals (1st ed.). Cheltenham, Australia: Aviation Theory Centre.
:3: www.youtube.com (2012) The Tenerife disaster in 5 min
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