Air Marshal Diptendu Choudhury (Retd), PVSM, AVSM, VM, VSM, Distinguished Fellow, VIF

The term Air Defence (AD), is simplistically understood by most as defence of a nation’s territory from an enemy’s air attacks. For a professional air power practitioner however, AD today means much more. It encompasses a wider responsibility which includes net-centric and integrated surveillance, defensive and offensive kinetic measures, for the protection of a nation’s airspace, territory and maritime spaces, in the larger context of national interest. From a national perspective, the proposed formation of AD Command therefore warrants a greater understanding of what AD is to the Indian Air force (IAF).

AD originated with the defence of cities, industrial and military assets from air attacks with Anti-Aircraft (AA) guns during the World Wars, followed by Surface to Air Missiles (SAM) in the following Cold War era. The dramatic improvements in Airborne Interception (AI) radars and Air to Air Missiles (AAM) ranges however, changed AD forever. From the Infra-Red AAM for within visual range engagements, to the radar guided missile which could hit targets beyond visual ranges (BVR), the AD capability of the fighter aircraft rapidly improved. This meant you could shoot down the enemy before it reached the target, or even before it entered your airspace. It also meant that AD fighter escorts could protect friendly strikes over hostile territory from enemy interceptors. The role of AD has since expanded beyond the limiting word ‘defence’, to include offensive capabilities well outside friendly air spaces, literally ‘taking the fight into the enemy camp’, well inside his territory.

Air Defence – An IAF Perspective

For the Indian Air Force (IAF), air power is doctrinally the total ability of the Nation to assert its will through the medium of air. It is prosecuted through an air strategy, and traditionally conducted through three campaigns in a conventional war. In todays limited war/conflict milieu, the campaigns are flexibly adapted into three main operations-Counter Air Operations (CAO), Counter Surface Force Operations (CSFO) and Strategic Air Operations (SAO), all supported by combat enabling operations. AD cannot be limited to a separate campaign because it is an integral and vital element of each and every air operation. To understand how it is so ubiquitous, some fundamentals from an IAF perspective are important for a deeper appreciation of this vital element of modern air power. Indisputably, air defence is the raison d’être of the IAF. What is not clear to most however, is that from a national security stand point, it actually translates to a wider construct of defence using the third dimension of the vertical medium. According to Jasjit Singh, India’s doyen of air power, conceptually the logical niche of AD is defence of India and protection of its interests and values, in the context of attributes and capabilities, a role it has kept performing over the years. To the IAF, AD includes ensuring the sovereignty of Indian air space in peace. During war or conflicts, it is ensuring the freedom of all friendly air and surface operations, in own and hostile airspaces.

Peace Time Role: AD has a pan-India peace time role in which it monitors, identifies and tracks, all air movements in the entire Indian airspace on a 24X7 basis, 365 days a year. The Indian airspace is segregated into military and civil airspaces, which during peace are utilised by both military and civil ac in close coordination, through a ‘flexi-use’ arrangement. But during operations or war, it becomes the sole responsibility of IAF. Total airspace management is no easy task which the IAF AD performs creditably. The minimal disruption of Indian civil aviation during the entire period of AD activation during and after the Balakot strike by the IAF, seen in comparison of the total airspace closure over Pakistan by the PAF, is testimony to this fact. The 24X7 radar surveillance over our own and hostile airspaces, along with the AD alert maintained by IAF fighters on Operational Readiness Platforms (ORP), have over the years led to innumerable live scrambles by interceptors, against all types of unidentified military and civil aircraft, drones, balloons etc. Then there are special AD activations carried out over vital areas or installations on special occasions like Republic and Independence days, when AD fighters and armed helicopters carry out Combat Air Patrol (CAP) missions against aerial threats. AD is not only everywhere it is on round the clock through the year, year after year.

Operational Role: AD has a humongous role in IAF operations during war, conflicts and the grey no-peace-no-war scenarios. Being the first line of defence, which is already active in peace, it seamlessly steps up the level of AD readiness to higher levels as and when necessary. The vast operational responsibility and role it plays are explained in the paragraphs that follow.

Surveillance, Control & Reporting: This is essentially a much-expanded version of the peace time responsibility of monitoring both friendly and adversary’s airspace. AD alert by the IAF is always the first operational activity undertaken at the first likelihood of an increased threat level. Within hours it swiftly redeploys all its radars, communications, weapon systems and AD fighters to their operational locations. All IAF AD sensorsand Surface to Air Guided Weapon (SAGW) systems, are put onenhanced surveillance watch, on a 24X7 basis. They are integrated in real time to the AD nodes, which exercise direct close control of armed fighters on ORPs in all airfields, to scramble them in minutes.

Integrated AD Kinetic Architecture: AD concepts have over the years evolved and expanded. From the older idea of point defence which provided coverto a single object or a limited area with AA guns, it has evolved into an integrated area defence (IAD) concept. An IAD system comprises of several SAGW systems of different capabilities and engagement ranges, integrated and arranged in tiers, which provides a much larger area of AD coverage. The volume of AD surveillance coverage has expanded exponentially with advanced radars capable of vast three-dimensional airspace coverage, radars which pick up and track very slow-moving targets just above the surface, to those which can track freefall and guided bombs, high speed cruise and ballistic missiles.

These are integrated into a multi-tiered ‘system of systems’ with an array of capabilities. Tier one is the surveillance layer where the threats are searched, detected and identified. The AD interceptors fit in anywhere amongst and across the tiers as the dynamic weapon. Tier two are long range SAMs which look deep into enemy airspaces hundreds of kms away. Tier three are the medium range systems which cover the intermediate spaces of less than a hundred km. Tier four is the low-level quick reaction short range systems which cover ranges in tens of kms. Tier five is the final close in weapon systems (CIWS) with extremely high rates of fire, which can even engage and destroy small precision and free fall bombs and missiles, to provide terminal defence. All AD interceptors and SAGW systems are totally integrated with surface and airborne surveillance systems, interconnected by high speed integrated and secure networks, and fused with advanced command and control systems to form the ‘AD Kill Chain’.

Area of Responsibility: Present and future AD concept of operations are no longer restricted to own airspace or maritime spaces or limited by altitude in its volume of coverage. With the improvements in stand-off targeting capabilities with our adversaries, it is about dominating the enemy airspace with BVR equipped AD interceptors and long range SAGW systems fused into an Extended & Integrated Air Defence (EIAD) system. Over the years, there has been a large expansion in the number of strategic facilities requiring AD in India. Vital industries, petroleum/hydrocarbon processing and storage facilities, power sector assets, ports and shipping hubs, vital data and network centres - the list is ever growing. These strategic facilities are all included in IAF’s EIAD umbrella, which is continuously expanding with inductions and integration of long-range and advanced AD sensors and shooters.

Air Space Management: This is vital and misunderstood AD function. It is a misconstrued notion that the IAF just wants to control the airspace, and inhibit the movements of other Services and civilian users. Nothing could be farther than the truth. All IAF operations- fighters, transports, helicopters and even Remotely Piloted Aircraft, in peace and war, are strictly governed by air space management norms, as is done the world over. During hostilities, the entire volume of airspace, including the Tactical Battle Areas of the Indian Army (IA), need to be closely managed so as to enable freedom of friendly air ops. This airspace is where all our air operations, including Counter Surface Forces Operations (CSFO) missions, operate or transit through, it is where the Intelligence Surveillance & Reconnaissance (ISR) aircraft operate, it is where the enemy air operates to support his forces and attack ours, and finally, it is also the same volume of airspace where all our artillery fire and long range weapons transit through. It is an intensely busy and dense volume of airspace which needs definite close control, to ensure we are able to detect, identify and engage each and every air threat, and permit full freedom of operations for our own. All offensive missions are closely integrated within the AWACS/AEWC aircraft and surface radar coverages, and closely coordinated with all friendly AD CAPs and SAGW elements. Over and above these, each and every air movement is intricately coordinated and de-conflicted to ensure safe routing through the enemy’s radar gaps, provided protection by our own AD ac and SAGW systems, and kept safe from IA’s weapon systems and firepower in the TBAs. Army aviation which often feels tied down by the airspace management norms in the TBA, need to appreciate thatit actually maximises their air operations, while ensuring AD coverage from enemy air, deconfliction with artillery fire, fratricide avoidance, deconflicting friendly air traffic, collision avoidance, and finally enable combat search and rescue.

AD Missions: They involve a variety of both defensive and offensive missions today which play a dominant role in protection of our airspace, civil and military assets, and most importantly ensures freedom of own air and surface operations. Defensive Counter Air (DCA) include CAP missions over own territory, civil and military assets and the TBAs, against enemy air strikes and their AD aircraft. In addition to these, all high priority offensive Counter Air Missions (CAO) and CSFO missions are provided with dedicated AD protection. These Offensive Counter Air (OCA) missions of Hi-tech AD fighters are tasked to ingress into hostile airspace to draw out and shoot down enemy CAP aircrafts (ac) before friendly strikes enter. For the safety of high value strikes, dedicated ac for Suppression/Destruction of Enemy AD aircraft form a part of the package. They specially target enemy AD radars and SAGW systems using electronic warfare jammers and anti-radiation missiles. To increase the chances of mission success and survivability, strikes are also provided dedicated AD escorts, wherever needed. All such high priority missions are executed under the AD surveillance and control provided by the Airborne Warning And Control System (AWACS) and Airborne Early Warning & Control (AEWC) aircraft which provide AD cover deep inside enemy territory.

AD of Intermediate spaces and the TBA: Protection of friendly surface forces in the Tactical Battle Area (TBA) comes under defensive AD. But the TBAs form only a limited part of the larger area over which the IAF conducts CSFO operations. Apart from the high value strategic centres of gravity targets deep in the enemy heartland, the IAF also conducts Air Interdiction sorties the vast array of vital counter force and counter value, infrastructure, logistics and communications, military and non-military targets, in the intermediate spaces. These missions are vital for isolating, shaping and assisting the surface battle but are often overlooked from a joint perspective. This is because of the Indian Army’s preponderant focus is on battlefield air strikes and interdiction missions limited to the TBA. The fact is that almost 80% targeting in IAF’s offensive missions are directly for the benefit of surface forces. And all these missions which are well inside the enemy territory, also need AD cover. Over and above these, dedicated CAP sorties, dynamically controlled by the IAF AD nodes, are exclusively provided for the AD of TBAs. In the future all IA TBAs would come under the IAF’s EIAD envelope, bolstering their AD significantly.

IACCS -The Warfighting Network: Today all IAF air operations are Net Centric Warfare (NCW) enabled. The backbone for this is the extremely successful Integrated Air Command and Control System (IACCS). This enables the entire air activity to be closely monitored and controlled, by a large number of AD Fighter Controllers (FC).

The IACCS enables a multi-layered transparency wherein, every individual air movement or mission within the entire networked airspace, whether own or the enemy, is monitored and tracked in real time. This network effectively links all sensors to provide an ‘integrated air situation picture’ into which the ‘sensor to shooter kill chain’ (SSKC) is networked. With the operationalisation of IAF’s Operational Data Link (ODL), very soon the aircraft cockpit would also be integrated to close the Observe Orientate Decide Act loop’ in real time. This means that the pilot in the cockpit is directly data-linked into the SSKC, thus enabling total net centricity of air operations. The IACCS is therefore a war winning combat enabler which today is the very backbone of the nation’s AD, one which is combat tested and proven in the recent IAF’s surgical strikes and subsequent operations.

Synergised Area AD: Challenges of the Future

It is important here to bring in the role of the AD practitioners of our sister Services. The original role of the Army AD (AAD), the erstwhile AD Arty, was essentially point defence of airfields, installations and small areas with Low Level AD (LLAD) guns. The effective ranges of these weapons were very limited, and strike tactics quickly evolved to stay out of their lethal zone. In future, the relevance of the legacy LLAD gunswill diminish further due to induction of advanced SAGW systems, and radar guided close in weapon systems (CIWS) for terminal defence as the final layer of the EIAD. This effectively means that from a defensive perspective, the vast legacy inventory of the AAD will be will increasingly be redundant in the EIAD concept. This is because the IA’s defensive formations will, automatically and adequately, be covered by the multi-tiered AD structure. It makes more operational sense, therefore, to have their new and future weapon systems integrated into a joint SAGW deployment plan, to bolster the area AD and activate at short notice. For the offensive formations, it would operationally prudent in the future, to retain only highly mobile SAGW systems for their terminal AD, since the maximum expected depth of surface penetration of these formations would be well within the multi-layered offensive EIAD coverage, extending well into hostile air space even in peace time. The ability for these mobile systems to plug-in at will into the ‘EIAD mainframe’ wherever they deploy, is truly the way of the future.

The present AAD, with its significant legacy assets and large manpower, will have to re-examine their future roles, especially since their large combat inventory is preserved for conventional war and not cost effectively utilised in peace time. An analysis of the peace time utilisation of IAF’s AD assets –fighter ac, airborne sensors, radars, SAGW systems and manpower, vis-a-vis those of the other Services, will underscore this fact. Given the widely accepted high probability of a low warning high intensity limited conflict, it is a national security imperative to have all AD assets deployed and ready to plug and play at very short notice. All sensors and shooters need to time share the AD readiness and alert status, to ensure their cost-effective utilisation in peace time as well.

The Indian Navy (IN) looks at AD as a warfighting function limited to its assets while at sea. While their overwhelming need for secrecy of their fleet locations is understood, the reluctance to contribute to the incidental AD surveillance whenever their sensors are available and are radiating, is not. This is especially so since advance warning of any enemy air threat to national assets, which includes Naval ports and bases, is invaluable for AD from a national standpoint. A push system, where the IN passes any relevant information into the AD mainframe whenever national assets are likely to be threatened, is the joint way ahead.

Misunderstanding of scale is another area of disconnect amongst the Services. AD comprises the largest role and more than half the assets (ac, sensors, weapon systems), infrastructure and manpower of the IAF. In comparison, it has a very limited role and composition in the IA and IN. A back of the envelope calculation of IAF’s open source inventory reveals 80% of the fighter ac are AD capable, and more than half the combat squadrons are dedicated to the AD role. Once all the radars, SAGW systems, networking assets and their totalregular running costs are added, the inventory is massive. This is the single most important argument as to why AD operations of the IAF cannot be pushed under a single Command.

Salience of Decentralised AD Operations

Since independence, AD of the nation has been the exclusive responsibility of the IAF, a responsibility in which it has invested heavily in terms of assets, manpower, training and operations. Given the immense range of responsibilities, and the large volume of airspace to be managed, the IAF AD today has become a system of systems which is operated by a team of teams. It under centralised control only for the sensor tasks of surveillance and data fusion. To optimise the management of the vast Indian airspace, and enable conduct of the wide range of air operations and AD operations in simultaneity, the entire Indian airspace is operationally distributed amongst the Air Commands of the IAF, each with a defined area of responsibility. While all the AD sensors are networked centrally through the IACCS to provide a common air picture, the shooter elements which consists AD fighters and SAGW units, operate under the AD Commander of each Air Command, within its defined area of responsibility. The key aspect here is that while surveillance can be centrally controlled at the national level, the size of our country necessitates AD operations to be decentralised to the Air Commands.

Within each Command, the AD operations are further decentralised to smaller sectors under Sector Commanders because of two vital facts; It is impossible for a single person to centrally command and control the vast range of AD operations, and take all the kill decisions for each element of the AD shooters, single-handedly. The second is that the vital ‘sensor to shooter decision making process’ has to be kept to the absolute minimum, for the AD kill chain to be swift and efficient. This ‘process’ is the very backbone of AD ops and has been developed and refined over decades of IAF operations, on a 24X7 basis. It has become a muscle memory with the thousands of AD pilots, FCs, AD system operators (ADSO) and SAGW combat crew, who have trained, operated and mastered the process, till it has become second nature. Since there cannot be any leeway in the swift identification-interception-engagement of air threats, the AD operations of the IAF are therefore best left decentralised to the Air Commands.

Some Thoughts on AD Command

While the decision for the formation of an AD Command has already been announced, it must be understood that there is huge difference in the responsibility of AD from an overarching national security perspective which is undertaken by the IAF, and that of the very limited role it plays in the other Services. The IAF had itself contemplated the idea of an AD Command and dismissed it as unviable, because the serious operational disadvantages far outweighed the limited gains. The sheer volume of airspace of the country and its areas of interest, the operational imperatives of swift response and tactical agility, and finally, because of the future ramification on aerospace defence due to the air and space continuum, dictated that AD could not be relegated to an independent formation.

Paths of Convergence: The fait accompli creation of AD Command must be seen as an opportunity for jointness. Convergence is necessary for a win-win way ahead where future operational capability, capacity and efficiency are not compromised, and the do-able is achieved. Some thoughts on it are:

  • First and foremost, it should essentially be an AD HQ with a defined functional role. The reasons as to why it should not be made into an operational command, elaborated in the previous paragraphs, are volume of airspace, scale of assets, decision agility and a swift kill chain.
  • Any organisation which has a24x7 live operational responsibility does not have the luxury of a transition period of re-adaptation. Any major change will mean a full revamp of the entire AD process, tactics, combat drills and SOPs. It will also entail, re-training of pilots, Fighter Controllers (FCs), AD Staff Officers (ADSOs) and SAGW combat crew on them. Simply put, we cannot shut down our AD even for a minute.
  • The primary role of AD Command should be focussed on the entire peace time airspace and maritime (coastal) air surveillance, control and reporting (C&R) functions, and civil aviation, towards a total sensor fusion. While the exercising of day to day control over civil aviation should remain with DGCA, command of the airspace should be with the AD Command. This will enable a swift and seamless transition to active control of civil aviation duringhostilities, contingencies and extreme emergencies. It will enable freedom of military air activity, enhancing AD response during operations, contingencies of airspace violations, hijack, sub-conventional threats and Air Defence Identification Zone (ADIZ) enforcement.
  • Ensure integration, security, maintenance and upgradation of all inter Service AD related communication and data networks. This should include multi-agency integration protocols and policies for civil organisations. The IACCS is a standalone network because the stringent and complex bespoke architectural, processing and security requirements of all IAF operations. The challenge of integration with the network structures of the other Services is that they are much more basic and limited in their primary applications – the Army’s ‘Akashteer’ is essentially for SAGW fire control integration, and the Navy’s ‘Trigun’ for maritime domain awareness. But if AD operations are to be integrated from a joint perspective, then both IA and the IN need to invest in adapting their networks with a ‘plug and play’ concept into the heavily invested, robust and combat proven IAF’s AD mainframe architecture.
  • Establish, maintain, man and operate the National AD Operations Centre which should be constructed directly under the aegis of the AD Command at a mutually suitable location.
  • Development of the much-neededand credible AD capabilities in our islands in the Indian Ocean Region (IOR), towards enhancing national security and strengthening the nation’s SAGAR strategy.
  • Let each Service maintain their AD assets and manpower to spread the capital and revenue expenditures, and to retain individual Service norms, ethos and administrative procedures. However, ensure inter-Service and multi-agency operational integration, and a cost-effective utilisation of all surface and airborne sensors and surveillance assets. This should include their operational employment, deployments, coordination of maintenance and servicing cycles, and integration into peace time operational responsibilities.
  • Carry out a centralised planning, upgradation and procurements of AD sensors and SAGW systems.
  • Conduct of operational audits, combat efficiency checks and inspections.
  • Issue, implementation and review of plans and policies with respect to trials, testing, evaluation and integration of AD sensors, weapons and networks.
  • Centralised, control, command, coordination and monitoring of all inter Service AD training agencies. This will include syllabus and curriculum definition, as well as monitoring of training standards.

Finally, and most importantly, the formation of the AD Command cannot and must not be seen in isolation or independently from the re-structuring of Joint Commands and theaterisation. This is because the ‘all pervasiveness’ of AD in all IAF operations. Any dilution of the IAF AD operational architecture, AD strategy and warfighting tactics, will have serious implications on national security. Therefore, restructuring for merely a joint command and control function, without considering the overarching operational ideology, roles, responsibilities and warfighting norms of a Service, would not be prudent.


Over the years AD with its offensive capabilities has long outgrown the limiting term ‘defence’. Its vastly increased capabilities have expanded its roles well beyond the erstwhile point defence construct. Operationally AD today is too serious a national security responsibility to be compartmentalised to a mere Command. With the increasing challenges of a no peace no war conditions, especially in view of the regional geo-political scenario, AD will continue to be the primary first responder. Given China’s increasing coercive national approach, the vital importance of Aksai Chin and the POK for its China Pakistan Economic Corridor, and Pakistan’s near total dependency on China, the threat of a limited conflict, independent or collusive, is alive and well. Also, the salience of the Indian Ocean for the nation’s economic growth and progress underscored by SAGAR necessitates a greater focus on AD of India’s maritime territories.

Under these circumstances, the formation of AD Command provides the opportunity fora functional re-configuration of the surveillance and networking at the national level, by integration rather than ownership of assets. Multi-agency NCW integration of all civil and military surveillance and C&R functions in peace time, synergising military and civil aviation, re-organisation of the AD order of battle into the EIAD concept, running the national AD operations centre in peace time, ensuring interoperability through procurement of standardised inventory, common SOPs, and establishing joint training and maintenance protocols, would be the pragmatic responsibilities of AD Command. Active operational AD should be best left to the robust, time and technology proven war fighting/operational norms of the IAF.

The IAF maintains a round the clock AD vigil and operational readiness, through the year, and year after year. Its capabilities, responsibilities and ubiquitous presence, need to be understood and viewed from a national security perspective. Today its employment philosophy and operational concepts have undergone immense changes from the past, beyond the limited point defence construct, towards an expanding the national security umbrella. Being an extremely dynamic branch of air power, it will continue to evolve in keeping with the advances in technology, the changing regional geo-political milieu, and growing requirements of national interest. Given the challenges of a tough and collusive adversarial neighbourhood, the growing coercive behaviour of the Dragon, and an increasingly unpredictable future, Indian AD has to stay alert, agile and adaptable in the nation’s interest, as the country’s first line of defence.

(The paper is the author’s individual scholastic articulation. The author certifies that the article/paper is original in content, unpublished and it has not been submitted for publication/web upload elsewhere, and that the facts and figures quoted are duly referenced, as needed, and are believed to be correct). (The paper does not necessarily represent the organisational stance... More >>

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