CHENNAI: Every day, thousands of aircraft cross the Indian subcontinent. Many never touch down: they overfly on routes between Europe, the Gulf and East Asia. Each is tracked, cleared and handed on by the Airports Authority of India (AAI), whose roughly 5,000 air traffic professionals work around the clock, every day of the year.
An official from AAI told TNIE that AAI is responsible 2.8m square nautical miles of airspace. About 1.04m sq nm is continental. The remaining 1.76m sq nm is oceanic, over the Bay of Bengal and the Indian Ocean. That is roughly three times India’s land area.
The task grows more demanding each year as airlines add aircraft, airports multiply and more Indians fly. Aircraft capabilities are also advancing, according to AAI sources. This puts the focus on Air Traffic Controllers, the silent heroes who will be marking their day on October 20, as their responsibilities expand with the growth of aviation.
Controllers must balance two goals that pull against each other: keeping aircraft safely apart and moving as many as possible without delay. AAI sources describe the work as walking a tightrope between the two.
The system is divided into air traffic service units, each with defined horizontal and vertical limits, running from the ground to 46,000 feet. Depending on their remit, they are known as ground control, tower, approach, area or oceanic control. A controller clears a flight from the engine starts to shut down at the destination stand, and hands it to the neighboring unit, in India or abroad, at each boundary.
Phraseology and procedures follow standards set by the International Civil Aviation Organization, so a clearance means the same thing in Chennai as in Chicago. Regulators scrutinize every instruction after an accident, incident or near miss. An AAI official likens issuing a clearance to guiding someone through a dark room by voice alone.
Entry requires intensive training and stringent qualifications. Controllers are then certified for their specific airport and unit, and are expected to keep up with changes to procedures, charts and phraseology. AAI sources say their physical and mental fitness is assessed regularly to ensure they can be called on at any time.
A bad night in the operations room, a ATC official says, is usually a cascade rather than a single failure. Monsoon storms over a major hub push dozens of aircraft into holding patterns while pilots ask for route deviations. Frequency congestion follows as crews talk about one another. The worst case is a lag in the automation displays, which forces controllers back to raw radar returns and paper flight strips, the official adds.
Emergencies shift the job from managing flow to protecting one aircraft. When a pilot declares a distress (“Mayday”) or urgency (“Pan-Pan”) call, the aircraft squawks 7700. Controllers clear space around it, restrict other radio traffic, alert fire and medical services and neighboring sectors, and feed the crew runway and weather data without asking unnecessary questions. A low-fuel flight is sequenced ahead of other traffic. For medical diversions, ground teams are arranged to meet the aircraft at the gate, the official added.
AAI officials say that AAI is investing more than Rs 1,500 crore in upgrades. The money goes on predictive software at regional centers that flags potential conflicts early, and on controller-pilot data links to replace voice radio over oceanic sectors such as the Bay of Bengal. It also covers a network of ADS-B ground stations to provide surveillance where radar does not reach, and security upgrades aimed at threats such as GPS spoofing.
For all that automation, the authorities' message on the day is that the human element remains central, as it praises controllers for their “dedicated service towards nation building."
