Enhancing Capabilities

ANS to improve air traffic flow management

The Airports Authority of India (AAI) is responsible for carrying out air navigation services (ANS) across all the airports in the country. The authority entered the area of air traffic flow management (ATFM) with the inauguration of a central ATFM (C-ATFM) system at the New Air Traffic Services Complex in Delhi in January 2017.

The total airspace served by AAI is 2.8 million square nautical miles (NM), comprising a continental airspace of 1.04 million square NM and oceanic airspace of 1.76 million square NM. Any traffic flying in this area falls under the direct control of AAI’s air traffic controllers. To ensure smooth air traffic services, this area has been divided into four flight information regions – Kolkata, Delhi, Mumbai and Chennai.

The three major components of ANS are air traffic management (ATM), airspace management, and ATFM. ATM includes aerodrome, approach and area/oceanic services, flight information services, alerts, search and rescue services, etc. Airspace management includes air traffic service route structures, airspace organisation, the flexible use of airspace, etc., while ATFM includes collaborative decision making among key stakeholders.

Integrated ATM system

ATM is primarily based on communication, navigation and surveillance (CNS) infrastructure. The communication component comprises air-ground (voice) very high frequency/high frequency (VHF/HF) radio waves, air-ground data link, and ground-ground voice and data link. The navigation component comprises landing aids such as instrument landing systems, Doppler VHF omnidirectional range (DVOR)/distance measuring equipment (DME), non-directional beacons, and satellite-based augmentation systems such as GPS-Aided GEO Augmented Navigation (GAGAN), and ground-based navigation systems. Meanwhile, the surveillance component comprises primary and secondary radars, ADS-B (automatic dependence surveillance broadcast), ADS-C (automatic dependence surveillance contract), and advanced surface movement guidance and control systems. This infrastructure forms the basis of ATM.

ANS Strategic Plan and augmentation

Air traffic movements between 1999 and 2015 are indicative of rapid growth and are expected to rise manyfold in the coming years.

In terms of developing effective air navigation systems, a step in the right direction has been the updating of the ANS Strategic Plan in 2014 by AAI, ensuring that it meets  the expectations of all airspace users and industry stakeholders.

Besides, in order to undertake the augmentation of the ANS infrastructure based on traffic growth, an aeronautical systems block upgrades (ASBU) plan has been formulated. In the short term, it (ASBU Block 0, 2017-18) will focus on infrastructure development which includes the extension of VHF radio networks and automatic identification and data capture under communication; DVOR/DME, GAGAN, performance-based navigation services; and radar, ADS-B and ADS-C, under surveillance. It also aims to improve air traffic control (ATC) procedures apart from integrated ATC automation, tower automation, controller tools, safety alerts, arrival manager systems, etc. Upper area harmonisation has been undertaken at Kolkata airport and will be soon adopted at Delhi, Mumbai and Chennai airports.

For the mid-term, the plan (ASBU BLOCK 1, 2018-2023) will focus on capacity augmentation. Within this, airspace sectorisation is an important component, a move that is likely to aid in traffic handling. Besides route optimisation, the creation of a radar network and amalgamation of 11 control centres into four en-route centres will also be undertaken. Further, C-ATFM, the transition to aeronautical telecommunication network, the implementation of GAGAN and ground-based augmentation systems are also key components of the plan.

In the long term (ASBU BLOCK 2, 2023-2028), the focus will be on optimisation. This includes the amalgamation of four en route centres into two centres, the transition from voice to data communication, a shift from ground navigation to satellite navigation, etc.


The Twelfth Five Year Plan projected domestic and international passenger growth at an annual rate of about 12 per cent and 8 per cent respectively. Meanwhile, domestic and international cargo is also projected to grow at a rate of 12 per cent and 10 per cent respectively, in the coming years. Besides, the recently introduced National Civil Aviation Policy is also expected to have a far-reaching impact on air navigation infrastructure by way of an increase in the number of airports and aircraft. It pushes for the flexible use of airspace, satellite-based navigation and traffic flow management. In this context, air traffic flow management is a new concept aimed at avoiding delays due to lack of landing space. The ANS Strategic Plan aims to address all these issues to cater to the projected traffic growth and meet stakeholder expectations.

Based on a presentation by C.R. Sudhir, Executive Director, CNS-O&M, AAI


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