Air Traffic Control (ATC), the system of controlling movement of aircraft at airport or in the skies, evolved as a profession in the post-World War period.
With increased importance of the role of Air Traffic Controllers, the International Civil Aviation Organisation recognised their services with the International Day of Air Traffic Controller, being celebrated on October 20.
K. Murali, regional secretary, Air Traffic Controller’s Guild, who was here recently, elaborated on the role of the ATCs and the evolution of technology that has seen huge increase in the number of flight services across the globe.
Though it is the pilots who fly the aircraft, for all practical purposes, ATCs are the ones who ensure safe movement of the aircraft, both in the airports and in the skies.
Air traffic controlling system started more of manual interaction with the pilots through ground-based radio equipment. It was ably assisted by the distance measuring equipment to assess the direction and position of the aircraft.
Free flight
However, this system came with limitations in terms of fixed routes or circuitous route for the aircraft. An aircraft flying from Madurai to Delhi would have to necessarily take a circuitous route through the airspaces of Tiruchi, Chennai, Hyderabad, Bhopal and Gwalior ATCs for effective control.
However, evolution of satellite-based onboard navigation system first broke this barrier. Using a combination of ground-based and onboard navigation system – called performance-based system – the aircraft were able to reach their destination through the shortest possible route, said Mr. Murali, who is also the Joint General Manager, Air Traffic Management in Chennai.
This free flight concept allowed the aircraft to decide their route based on various parameters such as the shortest route and economic height, and also free of weather-related problems, he added.
Vast airspace
Stating that India controlled an airspace that was four times the size of its land mass, Mr. Murali said that it had state-of-the-art equipment and its performance and capability was much better and reliable than those of many countries.
The advent of automatic dependent surveillance broadcast helped flying objects disseminate their position to the ATCs without the pilots’ intervention. This was more helpful in the oceanic air space, where there was no means of having ground-based equipment.
In India, such a facility was available in 14 airports, including Tiruchi.
The equipment helped not only reduce stress on manpower in the ATC but also get more accurate data, which improved the reliability of ATC services.
Besides, the controller-pilot data-link communication system allowed the controller and the pilot communicate through satellite-based system without having to wait for the aircraft to enter the ATC’s radio range.
Higher accuracy in determining the position of aircraft had brought down the safe distance between two flights on the same route to 40 nautical miles from 80 nautical miles in the past. Similarly, it had led to provision of five alternate routes within the available airspace as against one fixed route available in the past.
