Smoke On Go

The world’s worst aircraft accident – Instrumental in the development of CRM

583 people lost their lives in what was the most deadly aviation accident of all time. The subsequent  enquiry showed that from the very beginning of the event there were a multitude of factors that conspired to cause this disaster.

On that fateful day, Las Palmas’s airport had been closed temporarily because of a bomb threat that they had received.  Airliners that were inbound for the airport were diverted  to the smaller and not widely used airport at Tenerife.

The parking ramp there rapidly became congested. When the Las Palmas airport was again able to accept traffic, huge difficulties in sequencing aircraft for departure from Tenerife developed.  Eventually, KLM and Pan American Airlines, who were both operating Boeing 747s, became next in line for departure. 

To make the situation worse, a huge fog-bank rolled in over the airport, reducing visibility to as little as 300 to 400 metres.  ATC issued a taxi-routing that would require the KLM aircraft to leave the parking towards the upward end of the runway that was being used for take-offs.  They would  then backtrack all the way down the runway to its downwind end.  There was a turning circle there that was big enough  to  allow a  180 degree “U-Turn”  to be done so that the aircraft could then line up  for the take- off.

The Pan Am 747, as the second aircraft in the sequence, was instructed to follow behind the KLM 747.  However, halfway down the runway, it was to turn left onto what was the third of  four demarcated “connecting” taxi ways to the main taxi-way. This would place the aircraft  in a position where it  would be tracking  both  parallel to and also sufficiently separated from the  runway. At the end of the taxi-way, once the KLM aircraft had commenced its take-off roll, the Pan Am aircraft would enter the runway and line up for its own take-off.

The overall environment that existed at the time that all of this was happening was not conducive to flight safety. The airport’s parking and manoeuvring areas were saturated, the visibility was extremely poor and there was RT (Radio Telephony) congestion and saturation caused by the many aircraft , all with their own problems and frustrations , calling for departure slots and clearances.

 Within what was happening alone between  ATC, KLM and Pan Am, three different accents were at play, making it  difficult for the role-players to fully understand each other. There was heavily accented Spanish from the control tower, the  laid-back drawl of the  North Americans and then the  somewhat Germanic utterances from the Dutch. To make matters worse, very little standardised radio telephony procedures existed in those days, so it would be correct to say that there would have been an elevated level of ambiguity, confusion and misunderstanding of the instructions that were being issued . This would have resulted in no clear knowledge as to whether  the instructions  were in fact being adhered to.

The KLM aircraft duly reached the end of the runway, turned through 180 degrees and lined up for the take-off.  While this was happening, due to the restricted visibility, the Pan Am aircraft overshot the exit to the third taxiway. A dialog was then entered in to between its pilots and the ATC. The post-accident R/T recordings that were analysed, clearly revealed that an overall situation fraught with confusion, misunderstanding and uncertainty was developing and indeed escalating.

Valuable time was spent whilst the air traffic controller considered an alternative course of action that would result in a solution to the problem. The Pan Am aircraft was then instructed to proceed to the next turn-off, that being exit Number Four.  

Whilst the Pan Am aircraft was slowly and carefully finding the applicable painted line that lead it onto  exit number four, the KLM aircraft started its take-off run without having been cleared to do so. The co-pilot in that aircraft was sceptical about this action, as he had realised that there were just too many loose ends floating about, and he was concerned that the Captain was not situationally aware of what was happening around them. He had both wanted and attempted to obtain absolute confirmation that ATC had indeed cleared them for take-off and that the hold-up further down the runway did not present a threat. Due to an extremely steep cockpit seniority gradient that existed between he and the Captain, and also because of the fact that the Captain was impatient and wanting to get going, his inputs were ignored. The take-off run was commenced and the KLM 747, already at a high speed, ran into the Pan Am Boeing before it had fully vacated the runway. There were only 61 survivors, most of these being from the front of the aircraft which was already over the edge of the runway and above the connecting taxiway.

This accident had an enormous impact on safety within civil aviation. The need for a system whereby  crew members would be able to rapidly identify, assess and then manage threats and errors , accelerated the development of the human factor phenomenon what is called Crew Resource Management (CRM).

Then, within a very short time frame, a complete review of radio telephony procedures took place. It was obvious that the radio telephony procedures of the time were both deficient and flawed. In their place came the completely revised and practical “ICAO radio telephony procedures”. These procedures will be the subject of a future article. 




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