A night in Delhi's Air Traffic Control Room

It's two in the morning and I&rsquom at Air Traffic Control in Delhi. It is at this flat and spectral non-hour that SC Badola sits in front of a radar scope, looking at forty international flights over flying Indian territory simultaneously, and babying them across the sky between Banaras and Lahore.

 - Singapore can you increase your speed 5 knots
- Karachi estimate Alpha 4547&hellip
- Air France 147 Radar climb to 572&hellip   

All time is GMT, all those different accents of the Sky Captains are speaking a peculiar coded babel that sounds like English but isn&rsquot quite. My vision is blurring with sleep and the magnitude of all I have taken in the past three hours, while Mr. Badola is alive, clued in, talking to the alphanumeric blips on his radar scope, guiding them down VHF radio highways in the sky, keeping planes the mandatory eight miles apart, longitudinally, and a thousand feet apart, vertically. I can&rsquot even count all the blips on his screens, as he reads the short statistics that travel the screen with each airplane, and does complex vector geometry in his head, telling them the speed, height and direction they need to maintain&hellip

 - We&rsquore in the business of avoiding collisions.

It&rsquos like playing chess, long distance, with live explosives. The second most stressful job in the world after precision surgery. That&rsquos what they tell me. All the people in that long wide room lined with terminals and backlit maps of cities and flight paths. They&rsquore handling 450 &lsquomovements&rsquo (landings and take offs) a day, a movement every two minutes on an average, and over 200 over flights. Which seems strange, because they are the calmest and most collected people group of people I&rsquove hung around some time now. Especially Mr. RK Singh, the chairman of the ATC guild, who&rsquos showing us around the place.  I came in expecting &lsquoPushing Tin&rsquo pyrotechnics. Instead, the drab room buzzes with a low level hum of, um&hellip, Zen.  But the job is so nerve wracking that its mandatory to leave your post every two hours to rest, as the next controller takes over. During peak time takeoffs and landings, the controllers change every hour. And it&rsquos not too difficult to see why.

Air Traffic Control is a six hour a day, seven day a week job. No Sundays off, no vacations. Because of a shortage of a staff, they continually rotate shifts, so that the circadian rhythm has no hope in hell of settling in. A controller needs to build a complex three dimensional picture of  airspace and the aircraft flying through it. With upto forty to fifty aircraft in the air at any time, the only parallel is doing fifty trigonometric calculations. Simultaneously. With aircraft, approaching at their slowest, at two seventy kilometres per hour. The controller listens to one aircraft, listens to another, and yet another, thinks what to do, while watching the screen, entering data on the keyboard, replying to one, formulating a reply for the other, and yet another. All within ten to fifteen seconds. Its not uncommon to go &lsquodown the pipes&rsquo the mental hologram breaking down,  suddenly being clueless with what to make of all those blips frantically blinking on screen, drifting dangerously close&hellip

 - What do you do then
- The controller is taught to volunteer to get out of the situation, says Mr. RK Singh in his incongruously slow, relaxed way. And Area holds off releasing to Approach.

In controller-ese, the airspace is divided into three zones, often imagined as concentric cylinders, decreasing in both height and radius. There is Area Control, a 400 mile radius with heights upto forty six thousand feet, where the over flights are controlled. There is Approach control, a sixty mile radius, with heights up to twenty thousand feet, where flights coming in to land at Delhi are directed into a pattern to land in sequence. Once they line up to land, they are under Surface Area control, a radius of ten miles from the airport, and heights upto five thousand five hundred feet.   Control of aircraft is transferred from one Control to the other, as they take care of Area, Approach or Surface Movement. When things get too hot, with too many planes, and nerves fraying much faster than approach speeds, planes are held off in &lsquoorbit&rsquo&mdashaimlessly circling the perimeters of Approach Space, as you wake up from your comfy nap and wonder why you haven&rsquot landed in Delhi half an hour ago. Sometimes there&rsquos a medical emergency on board, and all other aircraft hold off in orbit, as that plane is given priority.

But the worst nightmare is weather. When Delhi&rsquos infamous fog starts rolling in between four and five in the morning, barely half an hour before the rush of morning departures starts at five thirty. Then there is complete and utter chaos, as planes queue up, and the planes coming in to land are circling as thick as buzzards over a garbage dump. Delhi&rsquos (ILS) Instrument Landing System is Category 3A (the highest is 3C), but that&rsquos not enough when pilots can&rsquot see the runway from &lsquodecision height&rsquo&mdashwhen they have to pull out of the landing pattern. To reach Category 3C, the airport will need massive structural modifications. Till then, planes will continue to be stacked in orbit, and controllers will have to deal with berserk radar screens. And ulcers.  

But it&rsquos not just about stress and radio frequencies and instant maths. In the tower, which controls landing and takeoffs ,the high windows give you a beautiful view of the runway, the road running parallel, and the sky all around.

The radio crackles. A Lufthansa flight is coming in&mdasha 747.
Cleared to land, it&rsquos a small dot, just visible in the sky, &lsquoBetween Saket and the Qutub Minar&rsquo.
Soon you can see the wing lights flashing.
The pilot asks for the centre line lights of the runway to be turned on, to increase visibility. And suddenly, as if by magic, a beautiful brilliant emerald necklace adorns the night out of nowhere.

And the 747, getting bigger by the second, all speed and streamlined grace lines up with the lights and touches down smoothly, in what has to be the most beautiful sight in the world.

Welcome to Delhi.