Do not be nervous, do not rush, do not interrupt: the story of one tragedy

    This week marks 42 years since the terrible terrorist attack in the Canary Islands, which led to the deaths of nearly 600 people. No, the bombing itself, launched by a fighter from the Canary Islands Independence Movement (the organization does not exist today; the author of this article is strongly against any form of terrorism ), only 8 people were injured. However, a series of subsequent events, including technical failures, irresistible external factors, flaws in personnel management, human psychology under stressful conditions and simply gross violations of the rules, has developed into such a tangle of incredible tragic coincidences that deserves the most careful analysis.

    So, on a clear day, March 27, 1977 afternoondue to an explosion in a flower stall and threats of another bomb allegedlythe key local tourist hub was closed - Gran Canaria Airport, located on the island of the same name, in the city of Las Palmas. An alarming message took unawares the aircraft bound for this paradise of the Atlantic Ocean, and for some it left no choice. The seventies was the heyday of the transatlantic and other long-distance transportations on the Boeing 747. Going into series in 1970, this aircraft remained the most spacious in the world for 37 years, and in those years it was even more perceived as a fantastic example of technological progress. But the infrastructure designed for such large cars in the world was still a little. With the closure of Gran Canaria, there was only one suitable airport for such monsters in the archipelago - Los Rodeos on the nearby island of Tenerife.

    One of these aircraft, for which there was no choice, was the Boeing 747 of flight 4805 of the Dutch airline KLM. The 50-year-old crew commander Jacob van Zanten was an outstanding pilot - 26 years at KLM, nearly 12,000 hours of service, of which more than 1,500 on the Boeing 747. He became literally the face of the airline, with his photographs printed brochures. For the previous six months, he served as a flight instructor of the company as an experienced pilot. In fact, he was already one foot in the position of top manager, but today this man was sitting at the helm of the plane of the ordinary flight Amsterdam - Las Palmas. Next to him is the co-pilot, 42-year-old Klaas Meurs and 48-year-old flight engineer William Schroeder. Following the instructions of the controllers, they turned to the island of Tenerife, landed and dropped off passengers in the building of the airport of Los Rodeos.

    Captain van Zanten

    This was not what the other Boeing 747 wanted - Pan American flight 1736 (Los Angeles - New York - Las Palmas). Commander Victor Grabbs, 56 years old, co-pilot, 39-year-old Robert Bragg and flight engineer 46-year-old George Warns piloted the Clipper Victor plane. It was an iconic machine that completed the very first commercial flight of the 747th: the New York-London flight on January 22, 1970. And without that, the crew, who had been in the air for a long time and made an intermediate landing, did not at all want to perform another forced landing. There was enough fuel in the tanks to circle over Las Palmas until the Gran Canaria airport was checked for explosive devices and opened again.

    But the dispatcher instructed them to leave for the alternate aerodromefreeing up airspace. Naturally, the only option cannot be optimal, and several wide-body aircraft have already landed in Los Rodeos, which created difficulties on the ground. At 14:15 flight 1736 landed. The airfield was small - one runway with one parallel taxiway. And all of it turned out to be clogged with a real traffic jam from planes - the Boeing 747 of flight 4805 was closest to the threshold of runway 12, behind it were the Boeing 737, Boeing 727 and DC-8; Flight 1736 was the last in line. He had no choice but to wait patiently for him to clear the way.

    Two airline employees took advantage of the hitch, boarding aboard to fly to the neighboring island.

    The unusual flow of airplanes to a small airport, which was served by only two dispatchers that Sunday, creates a nervous atmosphere on the ground. Car crews are looking forward to the Las Palmas airport opening to take off immediately and, having flown only 100 km, finally deliver passengers to their destination. And this soon happens - after only 15 minutes of landing flight 1736, at 14:30 the airport of Las Palmas announces its opening. Aircraft gradually start to run off to the runway and take off. The Boeing 747 of Flight 1736, as already mentioned, was the last in line. And in its beginning there was a delay. Captain of flight 4805 van Zanten, who had landed the car an hour ago, was now waiting intensely for all of his passengers to be at the airport and returned on board by bus.

    For a very long time, unions fought with airlines to ration work hours and improve working conditions. And in response, KLM's policy has become tough. If the staff does not want to recycle - well, he will no longer be allowed to recycle. Just leave the board if you do not fit into the standard shift time so that you do not dare to appeal more to difficult working conditions and overtime. But then the flight is automatically delayed until a fresh crew rises aboard. And passengers are allowed to land and accommodated in hotels, of course, at the expense of the airline. A conclusion immediately arises between the lines: for sure, the airline will follow, because of which crews it suffered such serious penalties?

    And now, when Captain van Zanten requested an extension of the working day at the airline’s office, the strict answer came from there: he should fly to Amsterdam before 19:00. From any Canary Island and by any means finding passengers - such problems did not worry managers, the flight had to be completed within the standard time frame. Naturally, captain van Zanten could not reconcile himself to what was happening - the delays threatened to turn into a crew replacement and transfer of the flight for a day, and he could not allow this stupid situation to affect his prestige and career.

    Finally, all the passengers were found, one guide girl decided not to return, but finally went down to the ground to see her boyfriend. But right away, another bad news came: Gran Canaria Airport was closed again for landing, because there were also traffic jams. The controllers did not give the airport in Tenerife permission to fly to the city of Las Palmas. The chances of flying to Amsterdam were slowly melting in time. Then van Zanten requested a full refueling of the aircraft, while they were waiting, so as not to lose time later at the airport of Gran Canaria.

    PanAm Boeing 747 behind KLM Boeing 747

    Looking at the gas tankers surrounding the KLM, flight captain Grabbs 1736 felt very annoyed. All other planes have already left the taxiway. Only the large silver 747th company KLM, surrounded by fuel trucks, still blocked their path, which the pilots even purposely went to make sure, stepping out onto the field and evaluating the dimensions, something was missing about a dozen meters to safely disperse. The American crew has been in the cockpit for more than 10 hours, and the senseless waiting for a plane completely ready for departure did not add enthusiasm to them. They had long had to leave the island of Tenerife, on which, in principle, they could not even board.

    In the meantime, an early evening began, and its unpleasant feature began to appear at the airport of Los Rodeos - a humid breeze and a slight cooling brought fog. And it was not a light haze spreading above the ground: in fact, low ocean clouds began to creep into the island of Tenerife, protruding high from the water, pouring in thick clubs into the valley where the airport was located.

    Clouds cover the runway of Los Rodeos airport - modern photo, photographer Manuel Luis Ramos Garcia

    At 16:45, the Boeing of flight 4805 finally finished a half-hour refueling and began to maneuver. The dispatcher, in view of the taxiways being occupied by planes, ordered flight KLM 4805 to go off to runway 12, drive it all and turn 180 degrees at the very end. Three minutes later, flight 1736 started the engines and was also instructed to follow the runway until the third exit, and then turn off and continue along the strip along the taxiway. Under the direction of the dispatcher, who spoke with a strong Spanish accent, both aircraft plunged into the fog that enveloped the runway. The runway axial illumination lamps did not work and the planes drove one after another slowly, gradually losing sight of the control tower, taxiways and each other. Nevertheless, the KLM flight was moving faster - Captain van Zanten was nervous and in a hurry.

    During taxiing, flight 1736 was completely disoriented. The dispatcher indicated turning to the third exit, but, unlike the first and fourth, it was not passing (at 45 ° to the runway), but sharply back with a turn of 135 °. In principle, there was nothing impossible in such a maneuver - after all, flight 4805 was to turn at the end by 180 °. But the fog, the absence of lights on the strip, the perplexity of why you need to ride in a zigzag and the doubts that the dispatchers, due to the accent, understood correctly, developed in the cockpit of flight 1736 into alarming uncertainty.

    By specifically asking the congress number, board 1736 received a rather clear answer - “Third. One, two, three - the third. " But the pilots, not familiar with the airfield, still doubted. Third, starting from the next turn? Or is it the first congress from which they taxied to the runway? And the dispatcher with a partner, sitting on the tower, generally lost both planes from sight in dense fog. There was also no surveillance radar at the airport to track the movement of aircraft on the ground.

    At 5:02 p.m., while flight 1736 crawled along the lane with a pedestrian speed of about 5 km / h, the dispatcher asked on the radio: “KLM 4805, how many exits have you passed?”, To which captain van Zanten replied: “I think we the fourth congress has just passed. ” Visibility was getting worse, and there was a threat to the KLM crew that it would fall below the limit. Then the Los Rodeos airport will stop giving permission to take off and there can be no talk of any flight to Amsterdam until 19:00.

    The dispatcher said on the radio: “Flight 1736, report back when you clear the lane.” The co-pilot Bragg, who was still looking for congress number 3, responded briefly: "1736."

    Van Zanten, meanwhile, reached the edge of the runway and began to turn the plane 180 degrees. The dispatcher said: “KLM 4805, report when you are ready to take off,” to which Van Zanten, concentrating on performing the maneuver, also answered shortly and not according to the rules: “OK.”

    Meanwhile, there were no reports from the PanAm 1736 crew that they had found the third congress - in fact, it was already left behind . At about the same time, Van Zanten again asked if runway centerline lights were available, and the dispatcher received a negative response. To this, the captain of the Dutch plane only grumbled: "And why am I not surprised."

    At 5:05 p.m. flight KLM 4805 fully deployed at the end of the runway.

    Two huge aircraft were now turned face to face, separated by hundreds of meters of impenetrable fog.

    Captain van Zanten switches the engine levers to idle, to which the co-pilot Meurs notes with concern: “Wait! We have not yet received the permission of the tower to fly. " Van Zanten impatiently said: “I know. Come on, ask! ”

    ATC clearance , or permission to take off on the route, is the approval of the aircraft heading controller after take-off and the moment the aircraft is transferred to another controller, but it is not a take-off permission. The latter must be obtained separately.

    Meurs requested the dispatcher. He replied: “KLM 4805, after take-off, take level 90. Turn right onto course 040. After passing Las Palmas beacon, get in touch with the dispatcher ...”

    Meurs repeated the instruction word for word, adding at the end not very clearly: "We, uh ... are going to take off . "

    The KLM crew’s headphone heard the voice of the “OK ...” dispatcher and a four-second crack.

    Radio communication in aviation is arranged in such a way that when tuned to the dispatcher’s frequency, any board can hear all the talks at a given frequency, but can speak only by holding the tongue, and only when no one else speaks at that frequency. This is called half-duplex communication — the radio only works on reception or transmission. You can speak for your part only after listening to someone else's message to the end. This is to ensure that the dispatcher calls and listens to each aircraft individually.

    When the second pilot of flight 4805 KLM announced that their board was about to take off, the dispatcher said, “OK,” and the next moment, to get it right, he pressed the tongue again and said: “Be ready to take off, I will call you.” At that very moment, the second pilot of Flight 1736 PanAm Bragg heard that KLM was about to take off and pressed his tongue, shouting: “No! Um ... we're still moving in the strip, 1736! ”

    The first button was pressed at 17: 06: 20.08 .
    The second - at 17: 06: 20.30 .

    Any of the messages was enough for Captain van Zanten to understand: either permission to take off had not yet been received, or that the same 747th was ahead in the runway. But the receiver mixed two input signalsfiled at the same time, and both of them turned into a local oscillator noise in the headphones of flight 4805.


    And captain van Zanten, according to the short “OK” dispatcher, having decided that the formalities of radio exchange were met , gave the full power of the engines. Flight KLM 4805 began to disperse.


    However, the dispatcher clearly heard the message from PanAm. He responded to Bragg's worried request: "I understand you, 1736, report back when you clear the strip." Bragg replied: "OK, we will report when we release." The crew of flight 1736 at that moment just reached the fourth congress. None of them knew that the KLM Boeing had already started overclocking. But Captain PanAm Grabbs, as if anticipating something bad, taxiing to the fourth congress, said: “Let's get the hell out of here!”


    Meanwhile, the KLM 4805 flight engineer, having heard the PanAm exchange with the dispatcher, exclaimed: “Is he still in the strip?” "What?" Van Zanten answered, barely holding the plane along the axis of the runway in the fog. “This PanAm - has he left the band already?” - repeated the flight engineer, to which van Zanten snapped: “Yes!”


    Captain Grubbs saw the lights of the Boeing KLM on the right in the fog and exclaimed: “Damn, this son of a bitch is coming right at us!” Co-pilot Bragg shouted, “Let's leave!” We are leaving! Let's go! ”, And the pilots gave full engine power, taking the plane from the strip to the left.


    Captain van Zanten, who had already begun to lift the car into the air, saw through the gaps in the fog a PanAm aircraft and desperately tore the helm at himself. But the heavy plane did not immediately take off from the ground, hitting the concrete part of the runway with its tail part and drawing twenty meters along it, carving a sheaf of sparks.


    The Boeing KLM still took off, and its bulged nose managed to fly over the fuselage of flight 1736, but the four main landing gears and the left-most engine at 300 km / h cut off the first-class cabin and the top of the Boeing PanAm fuselage along its entire length. Its tail and cabin fell off with a roar. The fuel from the torn off engine and the dislocated KLM tanks poured from above onto the PanAm and instantly ignited. Having lost the thrust of the left engines, 4805 flew two hulls and crashed onto the runway, along which another three hundred meters dragged it. Fully engulfed in flames, he turned across the strip at the ill-fated third congress, turning into a crematorium for all 248 people on board.

    Firefighters arriving at the crash site initially begin to extinguish the KLM wreckage, not suspecting that two planes were involved in the crash. But through the faults in the hull and along the untouched left wing of the flight 1736 aircraft, 70 people manage to escape, 61 of whom will subsequently survive.

    Burning Boeing of flight 1736 minutes after the crash.

    Debris of flight 4805.

    General plan of the crash site. In the center are the wreckage of the Boeing KLM 4805, taking off from left to right in the photo, in the background are the wreckage of the Boeing PanAm 1736, moving towards. In the foreground - taxiway, on the left - the third exit from the runway.

    The official investigation into the catastrophe provoked extensive discussion, but as a result the Dutch commander was at fault - captain van Zanten took off without the actual permission of the dispatcher. However, in this story it is interesting to make out all the intricacies of the factors that led to it.

    First of all, it is impossible to unequivocally call the disaster at Tenerife airport "a chain of tragic accidents." All the factors that led to it in the text of the article are highlighted in bold, and the terrorist attack, the accumulation of aircraft, which delayed both sides on the ground, and then the fog, which actually blinded all the participants in the maneuvers, are clearly chronological in this disaster. Other factors would be more correctly considered within the framework of the theory of “cheese holes”.

    Theory of Swiss Cheese(or holes in it - it doesn’t matter, the essence is still well conveyed by the name) likens the reliability of the system to several slices of cheese. The slices themselves are layers of protection, fault tolerance levels of the system in question. However, each such security system has a vulnerability built in or arising over time - a hole in the cheese. And if several such holes appear in one place, or become very large and overlap each other, then an external factor will penetrate these layers of “armor”, causing a system failure.

    Swiss Cheese Model, ill. - Wikipedia

    In the history under consideration, there are a lot of such "holes" due to the sudden influx of many aircraft into one airport. And some "expanded", appearing where no one was waiting for them. For example, congestion from aircraft paralyzes the operation of the airport and puts stress on the work of dispatchers, but in itself is not dangerous for cars on the ground. Everything could have worked out if the line of planes took off, using only the taxiway for maneuvers, but the taxiing of two planes along the existing runway had already widened the “cheese hole”.
    But in clear Canary weather two planes would see each other all the time during maneuvers. With the arrival of fog, everything would still be fine if you worked at the airport with a ground-based surveillance radar. It would allow to observe the relative position of the aircraft and prevent a collision. But this big "cheese hole" was already at the airport before the crash. Even the delay of flight 1736 on the runway could not play a role - but the incredible coincidence in timing of the two critical radio messages led to their overlay on the air, and the half-duplex technology of alternate messages did not help. And even this was not the final “slice” passed - the last role was played by the extra 50 tons of fuel on board the KLM, because it was because of them that the crew could not tear the car from the runway, desperately lifting its nose in a cloud of sparks.

    Another complex factor was the carelessness of radio communication. Informal words and an accent of the dispatcher accompanied all negotiations with both sides. In response to an ATC clearance request, the dispatcher named the van Zanten board “KLM 4705”, apparently due to fatigue and stress confusing the second digits of the sides 4805 and 1736 - an insignificant, but still a reservation. A minute later, in response to a worried message 1736 "We are still in the lane!" the dispatcher turned to him “Papa Alfa 1736” (spelling flight number, PA) for the first time for the entire radio. Speculatively, such an appeal could bring down the perception of the flight number by ear, as if it was addressed to some other plane.

    Yes, these specific little things did not affect the course of events. But in a global sense, it was a verbal trifle that led to disaster. After it, short “replies” like “OK” or “Roger” (“Accepted”) became unacceptable without repeating the message from the dispatcher — each air traffic participant was obliged to say on the air what he heard or just agreed with. Separately, the concepts of “take off” and “departure” were separately separated: now the departure route agreed with the dispatcher cannot be confused with permission to take off. And on that day, between life and death there was only a short "OK" dispatcher, said in response to the uncertain "we are going to take off" the second KLM pilot. And these two letters became the trigger for van Zanten, impatiently giving full throttle with the words "we take off."

    This point is also worth considering in more detail. It is impossible to do with the banal words "even very experienced people make mistakes." Of course, you can blame everything on Van Zanten's mistake and his desire to overtake the worsening weather. But why did the most experienced pilot behave this way? Indeed, experience is including the ability to prioritize work, and a person in such a responsible position could not but know how. Alas, it remains only to make assumptions on this subject. Of course, the first thing that comes up is the most logical explanation of what happened. How should a person feel, with a portrait of which there are leaflets full of high-flown words about Dutch craftsmanship, dedication and accuracy comparable to a clockwork? Forced to make an unnecessary landing delayed by passengers, a gas station pressed by their own company, telling common truths? Stupid unions drove him into the framework of formalities, stupid weather changes within half an hour, stupid separatists ruined his easy and ordinary flight. Of course, this puts pressure on emotions, spoils the mood. But is this enough for critical deviations in the behavior of the commander?

    KLM advertising spread. Note the headline: “KLM. From people who made punctuality possible. ” Was van Zanten nervous about the delays, knowing what KLM represents punctuality? We will never know.

    It could be so, if the dispatcher’s short vague answer was barely heard, his hand lying on the levers impatiently gave full forward. But something was not right before this: van Zanten gave a little gas right after the turn, worrying his co-pilot. Did he forget about ATC clearance? And then forgot about the separate permission to take off? Speculation is added by the fact that Van Zanten worked for KLM as a flight instructor for six months before this flight. His work included training newcomers in all the basics of negotiating with a dispatcher. Could he, speaking out the roles of air traffic controllers, involuntarily project this experience? To make a mistake, habitually saying all the standard phrases in your head, and not notice that you gave permission to take off to yourself?

    This is speculation, although not implausible. But there is another point. Next to van Zanten sat the rest of the crew. Did the commander forget or rudely broke the rules - but the co-pilot yanked him, saying: “Wait! We did not request ATC clearance! ” What went wrong?

    The captain’s phrase “I know. Come on, ask! ” known to us from the dry decryption of the black box. It is practically useless without facial expressions, intonation, emotions. But what did the second pilot see in the cockpit - a tired, irritated colleague or the authority of a commander whom he did not want to contradict? When the captain, who had barely heard the second pilot repeat the instructions of the dispatcher, interrupted him with the words “we are taking off,” he did not object for the second time to something like “wait, but now you need a separate permission to take off!” Perhaps the first and second sentences were pronounced with undisguised irritation? Or did the pilot feel that the commander was annoyed by his mistake with the ATC clearance, and when van Zanten missed the request for permission to take off, didn’t make him even more angry? The situation does not look so speculation, considering

    However, the crew’s concern was taking place, because the flight engineer’s question was whether the flight 1736 left the lane. And here, Captain van Zanten's full confidence in what was already sounded. The Dutch word “jawel”, spoken in the booth, has the meaning of not just “yes”, but a confident, reasoned “yes, exactly” or “so precisely” . Was it blind confidence in their actions, haste and irritation, or the manifestation of authority and submission to him? It is difficult to answer this question, but human psychology clearly played a huge role in why the flight commander 4805, without permission to take off, began its deadly acceleration.

    I note that the 1736 board that followed followed acted as the exact opposite of the 4805 board, which also led to disaster in its own way. After all, if they were moving along the runway faster or found a third exit, a collision would not have occurred. But the behavior of the crew is fully consistent with the behavior of an individual disoriented person. To admit that they did not see the necessary turn, notify the dispatcher about this, for the third or tenth time to ask if they need this congress, even if it leads back - the crew’s actions were constrained in everything, as if they were not flying, but were coming from blindfolded. General uncertainty due to limited visibility affected the entire behavior of the crew.

    And at the same time, despite errors and violations of the rules, both crews would have a chance to rectify the situation in time if in the set of insured moments, from the radio exchange to the presence of radar and direct visibility from the control tower, there would not be large holes that coincided.

    Robina van Lanscot, a guide girl, by the way, also violated the rules of air transportation, getting off the flight 4805 in Tenerife. But thanks to this violation, she was the only one left on flight 4805 alive.

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