THE TRICK IS NOT TO JOIN THE DOTS

The tragic loss of Korean Air Flight 801 this week will have forced air-traffic controllers around the world to face; .their greatest fear: that their blips and charts represent the lives of real people. John Carlin reports from Canada

It is rush hour over the North Atlantic and the planes on the air-traffic controllers' radar screens look like swarms of angry bees. Flights are converging over Newfoundland at a rate of 80 an hour for the night crossing from North America to Europe. It is high summer, the busiest time of the year, on the world's most congested transoceanic highway. From Toronto, New York, Miami, Chicago, Dallas, every day 900 aircraft make the journey across the ocean, double the number 10 years ago.

Gander, a small town where heavy traffic is three cars waiting at a red light, is the unlikely setting for this high-stakes drama. The pilots play their part but until they leave Newfoundland airspace their lives and those of their passengers depend on the instructions received by radio from the men and women at Gander Oceanic Air-Traffic Control Centre. It is a terrifying act of faith. A slight lapse in concentration from one of the controllers and the pilots could find themselves hurtling helplessly into an infernal aerial pile-up.

On this particular Saturday night Tom Crann is the supervisor in charge of shepherding the planes safely into the North Atlantic jet stream. He has 10 controllers working under him, each peering intently at a riot of little green blobs moving from left to right across a circular black radar screen. They have an allotted number of planes whose flights they must track. Crann moves from screen to screen, peering over the controllers' shoulders. His job is to have a clear vision of what all the planes are doing, to be alert to every contingency. In case of crisis, the buck stops with him.

Faced with such a frightening degree of responsibility, the natural impulse of most people would be to flee. But Crann's demeanour is steady and composed. A lean Newfoundlander with 28 years' experience in the air-traffic business, his voice is flat, his expression immutable, his humour dry. He seems to be a man incapable of panic. And yet he confesses that it is a feeling to which he could easily succumb were it not for his capacity to pretend, in a game he and all controllers play every time they go to work, that the little blobs on the screen are just that and no more.

"If you paused to consider that there are maybe four or five hundred souls in some of those planes you'd go nuts," he says. "On that screen right now you have something like 25,000 people. But I shut that out of my mind. It's like a surgeon: he operates on a brain, not a person. I call them 'li'l airplanes', that's what I do. 'Li'l airplanes.' And it works for me. You know that an error could be devastating, but you just lock that out. Otherwise you'd freeze."

AT A training school they have on the premises at Gander the students are told to imagine, as one of the instructors explained it, that "a whole bunch of marbles are rolling on a table and your job is to keep them from hitting each other." But in reality it is not quite that simple. Not at Gander anyway.

Making sure the planes do not collide is only part of the exercise. The critical factor the controllers must work into their calculations is that once the aircraft leave Newfoundland airspace heading east they will be out of radar contact for approximately four hours, until landfall over the British Isles or France. They will be flying, in other words, without scientifically verifiable bearings. New "Oceanic" rules must be enforced that do not apply when a plane is flying over, say, Europe or the mainland United States. The planes, in short, must fly significantly further apart. The challenge for Crann and the other controllers at Gander is to sift and separate the blobs that enter the left of their radar screens in such a manner as to ensure that once they disappear from the right of their screens they will remain sufficiently far apart from one another to be confident of uncluttered passage over the lonely North Atlantic.

Transforming chaos into order is the name of the game, but this is also a race against time. When the planes enter Newfoundland airspace they are flying five miles apart - the statutory minimum under radar surveillance. When they leave they must be 60 miles apart laterally and 10 minutes - about 100 miles - behind the plane in front. The planes are flying east at a remorseless 500mph and the controllers have an average of half an hour, at most 45 minutes, to get the job done.

THE OPERATIONS room at Gander Oceanic is large and windowless, the size of a basketball court, shaped like the interior of a large coffin. Three of the four white walls are lined with radar screens, each with its own computer terminal. The controllers, most of whom are men in jeans and T-shirts, sit on chairs with wheels, eyes fixed on the radar movements. Crann and another two supervisors sit at the centre of the room, like Captain Kirks, with their own machines. One of these is the computer masterscreen, displaying the location of every plane that is airborne across a map of the entire North Atlantic region, from the North American north-east to southern Greenland, Iceland, the British Isles, western France and the Iberian peninsula.

Crann peers over the shoulder of a controller, observing the progress of Virgin Airlines flight 012 from Boston to Gatwick. Crann presses a key on the computer monitor and little green letters flash up next to the little green blob informing us that Virgin 012 is a Boeing 747 travelling at a speed of 482 nautical miles an hour at an altitude of 35,000ft. The time is 10.35pm, but this is not a piece of information that is of any value to the pilot of Virgin 012. He is racing against the sun, eating up land hours. This is why he, in common with pilots and air-traffic controllers the world over, has his clock set to Zulu time, or Universal Time Co- ordinate, also known as Greenwich Mean Time.

The ceiling neon inside the operations room is lit in such a way as to create a sense of eternal dusk, an illusion of suspended time that is not discouraged when you step out into Gander itself, a town of 11,000, oddly removed from the world for a place whose economy depends on international air travel. The most eastward landmass in North America, Newfoundland would have presented a disappointingly forbidding spectacle to the first Viking visitors 1,000 years ago. A craggy, grey coastline gives way to bog, marsh and bleak, stunted semi-tundra landscape where short summers jump abruptly to long, bitter winters. A place, wrote E Annie Proulx in The Shipping News, "to scrob and claw through hard times". A visitor's guide book to the island, entitled (by a stroke of PR genius) Come Near At Your Peril, describes Gander as "young, modern and sophisticated", an impression that might be partly dispelled by a visit to the air-traffic controllers' favourite hang-out, the local curling club. In a classic of political incorrectness, the trophy for the winners of the annual club championship, prominently displayed in a glass box, is a stuffed white baby seal.

Most of the air-traffic controllers at Gander Oceanic are Newfoundlanders, a hardy, uncomplicated people whose accent seems to have evolved little over the centuries, retaining echoes of Irish and English West Country ancestors. Their modesty of ambition and philosophical calm are virtues the pampered passengers in Virgin's Business Class might not appreciate on Mother Earth but for which, while airborne over the North Atlantic, they should be truly grateful.

To the untrained observer, Flight 012 appears on the radar screen to be heading into frightful peril. Having just entered Newfoundland airspace, time 10.25 Zulu, it seems virtually to be touching wing-tips with a British Airways flight to London and a Northwest flight to Amsterdam, and poking the tail of a Paris-bound Air France jumbo. The actual distance between each aircraft is five miles but given the speed at which they are flying, and the fact that there are 30 other planes flying in seemingly suicidal formation to their immediate left and right, the mood in the operations room is bizarrely relaxed. No one is shouting, no one is jumping up and down. No more apprehensive than a crew of telephone switch-board operators on a light summer afternoon, the controllers talk softly to the pilots on their headsets. "Virgin 012, good evening. Report position please." "Good evening," responds a clubby English voice which sounds almost bored as it trots off a list of numbers, letters and enigmatic codewords like "Vixen". But it all makes perfect sense to the controller who digests the information first time and then informs the pilot that he is cleared to climb to 37,000ft, the altitude at which he will be crossing the Atlantic.

The next step is to get Virgin 012 on the correct "track". The tracks are the aerial highways, five or six parallel lines 60 miles apart, along which the planes must travel. This is known as the North Atlantic Organized Track System. The position of the tracks varies depending on the vagaries of the jet stream, a transatlantic wind that blows constantly from west to east but shifts a few degrees north one day, a few degrees south the next. The airlines demand that they catch that wind - and capitalise on the free 100 nautical miles an hour of speed it gives the aircraft. And Gander Oceanic - which receives payment of roughly US$100 per flight for its services - is duty bound to provide. "Vixen", it turns out, is a track that runs tonight along latitude 49 degrees north between two tracks either side of it, each 60 miles apart, at latitudes 50 and 51, 48 and 47.

Fifteen minutes pass and you can see some daylight begin to appear between the green blobs on the screen. Virgin 012 has set course along Vixen track, the British Airways and Northwest flights are heading towards their own parallel tracks. The Air France flight is also travelling along Vixen tonight but, having been ordered by the controllers to make a small change of speed, the safety gap with Virgin 012 directly behind is beginning visibly to widen.

Crann, who hunts moose and snares rabbits in his spare time, comes over to the screen and spots something he calls "a little bit of a routine nuisance". A plane is trying to cut diagonally across all five tracks. It happens quite regularly with flights, say, from Los Angeles to Madrid, which fly up along the Arctic Circle before swooping down in a south-easterly over Newfoundland. In this case it is a Canadian Airways flight from Montreal to Rome. What the pilot is going to try and do is the equivalent of a car crossing a five-lane motorway in heavy traffic. That, though, is not the nuisance Crann is describing. That's easy. Just a small matter of calculating the precise altitudes, directions and speeds of a dozen planes in a matter of one minute and, in the politest possible way, requesting the pilots of a Delta and an American Airlines flight to go up and down 1,000ft so as to get out of the Canadian's path. The movement of these flights then generates a whole knock-on effect which requires that amended instructions be issued to other planes in the neighbourhood.

But the nuisance is something else. The passengers aboard the Canadian flight have had to endure a slight delay in the serving of drinks, prompting the pilot to enquire whether he might drop down from 33,000 to 31,000ft. "Turbulence is a nuisance," Crann tells me. "Sometimes it's a real pain. Because these people are our customers and we want to please them but there are times when we just can't move them." Maybe the passengers are actually having a terrible time, maybe they are scared out of their wits. But, viewed from down below, the Canadian Airways pilot is being a bit of a churl asking to drop altitude on top of all the other complications he is causing. If that is what Crann is thinking, however, he is not showing it. He and the radar controller talking to the pilot exchange a couple of knowing monosyllables and, cramming decades of combined training and experience into 20 seconds, they come up with a plan which will allow the pilot to have his way and the passengers their dry white wines.

Crann and his controllers give off only the subtlest sense of tension. Rationally you understand that they have to be under intense pressure. (The controllers at Gander Oceanic's counterparts in Britain, the Scottish and Oceanic Area Control Centre in Prestwick, have the most stressful job of all UK air-traffic controllers, including those at Heathrow, according to an official review done a few years ago.) But the pressure is not visible. Like a swan gliding over a lake: it looks so serene on the surface yet you know that underneath the swan is paddling away frantically.

But for Virgin 012 it is all plain sailing. No turbulence, no altitude changes. The little green blob now on the centre of the screen is nestled a comfortable distance away from all the other blobs in its immediate vicinity. But suddenly something happens. Something completely unexpected and extraordinarily unusual. Crann, who until now had been moving in slow motion, dashes to inspect one radar screen, and then another. There is a buzz in the room there hadn't been before. The eight radar controllers who had been on duty at the screens are joined by two more Crann has summoned in from their coffee breaks.

It turns out that the transponder aboard a Boeing 747 has packed in. The transponder is the electronic mechanism that conveys the radar signal which appears on the radar screen in the form of a blob. With merciful alertness one of the controllers realised there was a ghost in the machine. The 747 was out there but you couldn't see it. What was worse it was travelling against the traffic flow, the only plane entering Newfoundland air space from the east, from Europe. Like a mad bull running into a stampede. Transponders very, very rarely pack up. Yet at Gander they have a contingency plan ready in the event of something like this taking place. And Crann knew exactly what it consisted of.

The first principle, as with mad bulls, is to give the rogue 747 as wide a berth as possible. When aircraft re-enter the radar zone from the ocean they are instructed to narrow the separation distances with other aircraft. The statutory 60-mile gap is reduced to five miles. In this case, though, Oceanic rules will apply all the way until the plane lands. Time is of the essence if, as the outrageously understated Crann puts it, "an incident" is to be avoided. Three minutes is how long it takes for the controllers, with Crann doing the orchestrating, to instruct, first, the flight crew of the invisible 747 to drop altitude, change speed and alter course, and then a number of other planes flying towards it to amend their trajectories too.

The crisis passes. The 747, more dangerous for a while than a stealth bomber, cruises safely through. Most of the pilots in the advancing eastward wave are blithely unaware that anything out of the ordinary has happened. Crann sits down and sips at a cup of coffee. "That was a little hectic," he says, allowing himself a thin smile.

Somehow, "incidents" never seem to happen. "Emergencies", on the other hand, yes. No one at the operations room could remember the last time a transponder had failed but an emergency, as they call it, can be relied upon to come up at least once a week. There had been one earlier in the day, around lunchtime - rush hour on the westward Europe-North America run.

Shelley Goulding was one of the controllers on duty. The pilot on Delta Flight 33 from Munich to Atlanta had radioed from the middle of the Atlantic that he had a medical emergency. A child on board had had a seizure and he had to divert the flight urgently to Keflavik, in Iceland, for hospital treatment. "He was in the middle of the middle track at the busiest time of the day," Goulding said. "He was flying at 33,000ft and at every level above and below the planes were stacked up." The trick was to get him down through heavy traffic to 28,000ft, where the airspace was clear. And to do so without being able physically to see the positions of the other planes because - and this is a function of the curvature of the Earth - they were all outside radar contact. On the strength of the latest information as to where each plane was, which can be relied upon entirely only if the pilots have stuck rigidly to their flight plans, the controller at Gander talked to the pilot by high-frequency radio. "We told him he had to get down to 28,000ft on his own but we advised him exactly where all the planes around him were, which level below him at which time would be free." Delta 33 made it down to Keflavik safely, deposited the child and then took off again without further complications for Atlanta.

"We get these situations also when a pilot asks to land to drop off an unruly passenger," Goulding said. "We had a case recently of a woman who took all her clothes off in the plane and the pilot diverted down here to Gander. That sort of situation is much more pressing when a plane has lost an engine - especially now that we have a lot of twin engines crossing the Atlantic," Goulding said. "That's the kind of thing that really tests the system. That's what you're paid for. When something like this happens you just handle it. If you let it alarm you, you can't do the job. You can't be hot-headed. You can't cave in under pressure. That's why all the people here are very laid-back."

That is a quality which Goulding, who is 29, has in common with her fellow controllers but it may be the only one. Unusually, she comes from an arts background, having graduated from university with a degree in English literature. Born and raised in Gander, she swore when she was a teenager that she would fly the coop and settle in a big city. But she married and stayed, compensating for her small-town frustrations by travelling as often as possible to far-flung places. She adores the theatre in London, the buzz in New York. Last Easter she went to the Middle East. Most of her colleagues thought she was out of her mind. Yet she loves her job, the discipline it requires, the coolness under fire, the responsibility.

Like Crann, the one thing she will not allow herself to do, though, is dwell on the enormity of that responsibility. "A couple of times I had cases of medical emergencies which I responded to in the usual procedural way only to find a few minutes later a message on my screen sent by the pilot saying: 'The passenger has expired.' Then the emergency is over for me and the pilot just keeps going but it is at moments like this it really hits you that there are real people on board. You wonder if his wife is with him, how she will react..."

She experienced a similar shock of recognition when she heard the news last year that TWA 800 had exploded in mid-air. "I had goose bumps. I nearly threw up. Because I dealt with TWA 800 every night. Again it brings home the thought you never want to contemplate, that there are people up there. I would have talked to the pilot, I'm sure, many times."

Days and nights pass, though, for weeks on end, without Goulding or any of the other controllers having to confront the potentially paralysing thought that one small mistake could plunge hundreds of people to their deaths, thousands more into deepest mourning. Virgin 012, for example, might as well have been a figure in a video game for all the emotions it generated among Crann and his fellow controllers.

It passed through Newfoundland radar without raising so much as an eyebrow, venturing out into the blue yonder wrapped inside a "protective tube", as Crann described it. The dimensions of this imaginary tube are determined by the statutory minimum distances that must separate the aircraft. So long as the pilots don't have a brainstorm and deviate without warning from their stipulated speeds, altitudes and latitudinal tracks, the passengers can cheerfully participate in the delusion that theirs is the only plane in the sky.

Late into the night a glance at the master computer screen in the middle of the operations room, the one with the map showing the position of all air traffic across the entire North Atlantic, shows just what a remarkable job the good shepherds of Gander have done. The picture in mid-ocean no longer suggests a swarm of angry bees. Virgin 012, the BA flight to London, Northwest to Amsterdam, Air France to Paris and 200 other planes are advancing south of Greenland and Iceland towards Scotland in perfect formation, like an orderly army of ants.