Has the Time Come to Replace Manned Combat Aircraft With Armed Unmanned Aerial Vehicles?

The F-35 should be, and almost certainly will be, the last manned strike fighter aircraft the Department of the Navy will ever buy or fly.
– Ray Mabus, US Secretary of the Navy

Aviation, which started with the Wright Brothers’ first controlled flight of a heavier than air machine on 17 December 1903, has come a long way in the last 114 years. As is true for many technological developments, aviation too quickly acquired a niche for itself in the military matrix. Manned aircraft were first inducted in warfare as high ground observatories to monitor enemy troop movement. Aerial reconnaissance with an observation by the pilot and later with a still camera was the first operational role of aircraft. The next step involved aircrew carrying small bombs and dropping them manually from the cockpit. Thus was born the role of ground attack. In the next phase, aircraft were equipped with guns to engage enemy aircraft in the air and this commenced the aerial combat role. Besides these, the development of bigger airframes and powerful engines enabled the development of transport aircraft, which were subsequently modified with the fitment of radars, jammers and fuel tanks for surveillance, electronic warfare and inflight refuelling, respectively. These roles are being performed by manned aircraft albeit with much better technology and accuracy than was possible during the 20th century.

Technological advancement in computing and communication facilitated the development of Unmanned Aerial Vehicles (UAV). Controlled from a ground station, the UAV either flies a pre-planned path or can be dynamically controlled. As was the case with manned aircraft about a century ago, the operational roles of UAVs are following a similar trajectory. Besides being used as a weapon, the first operational role for UAVs was of aerial reconnaissance wherein the UAV was fitted with optical cameras. The development of sensor technology and its miniaturisation along with better computation and communication allowed transmission of real time data in various electromagnetic bands, a boon for a military commander. UAVs scored substantially over manned aircraft in this role owing to their longer endurance. Coupled with satellite imagery capabilities, UAVs have practically driven out manned aircraft from the reconnaissance role except in a very few critical cases where their low speed remains an operational impediment. However, UAVs have been able to overcome their speed limitation to a certain extent by their low Radar Cross Section (RCS), making it difficult to detect and engage them.

Going by the precedent of manned aircraft, the next role UAVs were assigned was of ground attack. This required more powerful engines and larger airframes for enabling the UAV to carry weapons. Here too, technology played a pivotal role in enhancing weapons delivery accuracy thus reducing the weapon size required for the same extent of impact on the target. This role by UAVs is being carried out successfully in Afghanistan with Hellfire missiles from USAF MQ9. The UAV’s long endurance allows a high success rate for search and strike missions as compared to a manned fighter aircraft with comparatively limited endurance. The success rate of UAV ground attack missions is to a large extent dependent on their operation in a benign air defence environment.

The full development and employment of UAVs in an air defence role is still some distance away owing to prevailing technological challenges. In the same vein, switching to unmanned transport aircraft may also take a few decades. While the roles of UAVs are gradually increasing in the civil sector, ranging from the delivery of packages to the shooting of high-quality aerial films, a debate is on about the end of an era for manned aircraft for operational missions. There are three critical components involved in the employment of UAVs instead of manned aircraft in combat, viz, basic flying (take off, landing and planned navigation), tactical flying (situation appreciation and changing the plan midway) and weapon delivery (correct and timely targeting). While progress has been made in all three verticals, it is yet to reach a level that would enable the complete replacement of manned aircraft. Factors that need to be considered in this debate are:-

Sensors and Dynamic Situation Processing. In a benign air defence environment and uncontested air space, UAVs are efficient in mission accomplishment. When decision-making autonomy is required or there are rules of engagement or a developing air situation that cannot be explicitly expressed mathematically, a human is essential. The current generation of sensors do not have the capacity to replicate the appreciation by a human eye and pose a limitation in operations because the UAV operator is not situationally aware. The major drawback of the current generation systems is their inability to capture high fidelity data, process, encrypt and transmit it and, based on directions from the ground station, receive, decrypt and process it to execute a command. Based on the type of processor and communication systems, this process may take anywhere from 600 milliseconds to three seconds – a very long duration in combat operations. The development of Artificial Intelligence will overcome this deficiency and provide the requisite autonomy to the UAV.

Speed and Manoeuvrability. UAVs are generally characterised by their low speed and consequent low manoeuvrability as compared to manned fighter aircraft and this makes them vulnerable. At the same time, however, a low RCS and greater endurance are design features that assist UAVs in mission accomplishment.

Weapon Carrying Capacity. Owing to their power, UAVs are capable of carrying low calibre/low weight weapons in limited numbers as compared to manned aircraft. But this limitation can be overcome by converting fighter aircraft into UAVs or through the use of special weapons with high accuracy to reduce Over Target Requirement (OTR)1 in terms of number and size of weapons.

Quantity and Costs. UAVs do not need some of the safety and operating systems that manned aircraft need and thus enjoy better cost efficiency. This normally translates into greater numbers of UAVs for the same cost as compared to a combat aircraft. However, autonomous aviation technology is yet to mature, which can be assessed from the fact that UAV accident rates are four to five times higher than that of manned aircraft. This negates the cost effectiveness partially as of now, but is likely to improve with better technology.

Endurance and Risks. UAVs practically eliminate human endurance as a factor for mission duration. Autonomous inflight refuelling could keep the UAV in the air for days. Risk to life and risk of capture of operators is fully eliminated. However, the control of UAV is heavily dependent on electromagnetic waves, which are susceptible to interference/jamming/technical malfunctions. Any delay in the transmission of critical commands could be lethal. Another aspect of the absence of an aircrew in UAVs is the limited ability of on board systems to diagnose any system malfunction especially owing to an external factor. An aircrew can diagnose an instrument failure and react to save the aircraft, but an UAV with instrument failure will most probably be lost.

Trends. With effect from 2010, the induction of UAVs has outnumbered induction of manned aircraft in the US armed forces. And since 2011, the US Air Force has trained more UAV pilots than fighter/bomber pilots. But most of the financial allocations the world over including in the US are still being made for manned aircraft development and procurement. This will change once better processing power, artificial intelligence and communication equipment are developed and incorporated in UAVs. Technology involving a swarm of UAVs operating in a group and being mutually supportive is at an advanced stage of development and will assist UAVs in garnering a greater share of operational missions.

Efficacy. The conversion of fighter aircraft to UAVs for undertaking training missions has been tried and tested in the cases of the F4 and F16 in the US Air Force and the F6 in the People’s Liberation Army Air Force. The same could be developed further for undertaking operational missions with high risk.

Suitable Missions. In the foreseeable future, an optimal solution is a mix of manned aircraft and UAVs till technology can support a better appreciation of situational awareness and command and control aspects. Currently, the most suitable missions for UAVs are the five Ds – Detect, Designate, Dirty, Destructive and Dangerous. Detect missions require long endurance and are pre-planned and repetitive in nature like surveillance over a large area for a prolonged duration to detect a possible development. Designate either in conjunction with Detect or stand-alone missions designate a target system/sub system using laser designators for an attack by an armed aircraft/UAV. Dirty missions are undertaken in an NBC environment in order to negate the risk to human life. Destructive missions are when the UAV is equipped with explosives and is used as a weapon And Dangerous missions involve those against a heavily defended target to either attack the defences or force the adversary to expend missiles on UAVs.

Indian Scenario

While Israel and USA are leaders in UAV technology and operations, the Indian UAV programme is in its infancy. Going by the example of the Light Combat Aircraft (LCA), the production of an Indian combat mission capable UAV is at least a couple of decades away. India will have to depend on imports or joint ventures for Make in India in the interim, as UAVs are essential in any operational matrix. Till a requisite number of mission capable UAVs are inducted in India, some of the operational missions will have to be carried out by manned aircraft, albeit in a suboptimal way. The induction of Su30MKI, LCA and Rafale will continue till 2022 and these aircraft with an average calendar life of 25 years or more will be in service well beyond 2050. By that time, for operational effectiveness, at least 50 per cent of combat missions would be designated to UAVs and that would require a large fleet of various types of UAVs. To meet that challenge, it would be prudent to establish a joint venture for the production of UAVs in India under the Strategic Partnership programme.

Sum Up

With the current state of technology, UAVs are the best bet for operations in an uncontested air space for surveillance and search and strike missions with low calibre high accuracy guided weapons. However, operations in a moderate to dense air defence environment will need manned aircraft to react appropriately, although UAVs can be of great value in reducing the risk to manned aircraft by saturating the air space and attacking air defence systems thus compelling an adversary to expend his missiles. UAVs are essential ingredients of a combat force and their role will continue to increase along with their capability. A quantum jump in the operational role of UAVs can be expected only with a breakthrough in AI. Until that happens, the role of UAVs will increase gradually to reach about 50 per cent of combat operations over the course of the next three decades.

Views expressed are of the author and do not necessarily reflect the views of the IDSA or of the Government of India.

• 1. Over Target Requirement (OTR) is the number of weapons required over a target to achieve the requisite level of damage and is calculated based on target system, its functional and vulnerability analysis along with weapon characteristics and parameters of its damage mechanism like Blast Over Pressure, Dynamic Pressure, Pressure Pulse, Penetrative Index, Fragmentation Pattern, Shock and Fire Indices in the given attack profile.