Air traffic controllers
Air traffic control is like playing chess in three dimensions – using potentially explosive pieces. If you are careful and keep a cool head, nothing will go wrong. The moves are all in the rule book, and there are computers to help plan each one and predict the consequences. Nothing should go wrong. Except, sometimes, it does.
On November 26, 1975, an air traffic controller at Cleveland, Ohio, had just taken over from a colleague. He had been looking at his radar screen for only 55 seconds when he realised he was watching a disaster about to happen.
An American Airlines DC-10, flying east from Chicago with 194 people on board, was climbing to its assigned position of 37,000ft. A TWA jumbo flying west with 114 people was cruising at 35,000ft. The controller realised that the two airliners were heading for a midair collision near Detroit, and it was only seconds away.
Reacting instantly, he made an urgent call to the DC-10: ‘AA 182, Cleveland, what is your altitude?’
The reply came back from the airliner: `Passing through 34.7 (34,700ft) at this time. We can see stars above us but we’re still in the area of the clouds.’
Controller: ‘AA 182, descend immediately to 33.0 (33,000ft).’
On the flight deck of the DC-10, Captain Guy Eby responded instinctively, pushing forward his control column. The plane pitched over with a stomach-churning heave, and unbelted passengers, air hostesses and food trolleys flew into the air as the floor plunged away beneath them.
For a brief moment, Captain Eby saw his windscreen fill with the TWA jumbo as it passed just overhead at a combined speed of 1000mph (1600km/h).
Flight data recorders later showed that the DC-10 had been within 47ft (14m) of the jumbo’s altitude when it dived to safety.
The incident spotlighted the ideal qualities of an air traffic controller: concentration, patience, swiftness of decision, and an authority that can be trusted instantly by pilots.
Trainee air traffic controllers need basic fitness, good eyesight, clear speech and school-leavers’ qualifications that include English and a science. (English is the international language of the airways.) In their training, would-be controllers have to absorb technical information about aviation law, meteorology and radio theory, in addition to the formalities of communicating with pilots.
Trainees study in classrooms and on simulators, with practical sessions at control centres and airports. They are then posted to an airport or a control centre for supervised work and further training.
The intense training prepares them to analyse and act upon the mass of ever-changing information on their radar screens when they finally qualify as air traffic controllers. A major airport like Frankfurt handles an average of 805 flights a day – one every 60 seconds at peak hours – and a controller’s radar screen may show two dozen images at any one time, all of them moving, all with pilots awaiting instructions.
But no amount of intellectual ability or technical knowledge can give a controller the essential personality skills needed to manage the task effectively. At some international airports, the pressure is so intense at times that controllers have reportedly collapsed. Certainly, in every major airport, the level of concentration and the responsibility is highly stressful.
No wonder Britain’s National Air Traffic Services, which take on more than 100 trainee air traffic controllers a year for 18 month courses, say that candidates must have ‘a calm, even temperament, alertness and quick reactions’.
Dedication and self-discipline help, too. It is often a lonely occupation, involving shift-work through the night. Though in small airports controllers can watch the planes manoeuvring, in large airports many sit continuously in dimly lit rooms in front of radar screens. They never see the.aircraft, and may have little direct contact with other people.
Conversation during working hours is often reduced to orders in the formal phrasing needed to ensure clarity and accuracy: ‘Roger, seven-three-two. Descend to three thousand feet on QNH
It’s not everyone’s idea of fun. But the challenge of the job, the responsibility and he rewarding salaries ensure that there is no shortage of applicants to be air traffic controllers. But only one applicant in 20 is accepted as a trainee.
Tracking by numbers
The screen in the radar room at Washington’s National Airport allocates a flight number to the planes in its airspace. So the movements of each plane can be seen and tracked by radar.