Over the last few decades multi-role aircraft have become essential platforms for air forces determined to gain maximum flexibility from their air fleets. The choices available have been spread across a very wide range of airframe designs, encompassing military versions of commercial turbo-prop and jet air transports, former large bombers, business jets and utility aircraft, as well as specialised variants developed from fighter-bombers and, increasingly, unmanned air systems.

The high costs associated with air platforms fitted out with complex electronic systems required for Intelligence, Surveillance and Reconnaissance (ISR) duties has favoured the use of well-proven airframes powered by reliable and easy to maintain engines. The sales potential for these specialist aircraft is relatively small compared to the large numbers needed for front-line air defence or attack squadrons, or in the commercial airline market, but this reflects the fact that only limited numbers are required to provide the data and situational awareness that military commanders are seeking. In terms of capital investment they can benefit from customers leveraging the value from big-selling civil orders to keep airframe costs down, but the purchase, development and integration of advanced electronic sensors and their supporting computer systems and displays, plus provision for system operators, increases the unit costs. Added to the platform and on-board system costs are the associated special crew training requirements and support testing and maintenance over an extended service life, which may require regular system upgrades to manage the vast data flows that can be generated on missions involving multiple sensor data acquisition, and the chosen methods of recording and distributing the information.
Depending on the customer’s needs, priority might be to carry out data selection and editing on board the aircraft by system operators, for more detailed analysis after this has been downloaded and removed to a ground interpretation centre on completion of the sortie. This implies an aircraft platform which is large enough to carry all the sensors and several display work-stations for the many cabin operators, and sufficient cooling for the powerful computing equipment that is carried. Equipment and displays to be used in the air require very robust construction and expensive degrees of integration and testing before they can be declared operational. That naturally includes secure connectivity and extra hardening against interference, but also special attention so that features, such as touch-screens, offer the right level of positivity in operation, perhaps in turbulent skies, and the ability to remain easy to see in differing ambient conditions from darkness to sunlight. For this reason most civilian-derived aircraft usually have minimal cabin windows when used for ISR or other Special Missions, such as Electronic Warfare (EW).
Alternatively, the sensor-receiving platform might act more as a node in the battlespace network, and have a primary function to collect the data and re-distribute it to a ground-based interpretation team, or military headquarters, or other air platforms. As digital developments in electronic systems become more capable and more compact, carrying out greater analysis of data, the speed of operation is increasing along with the miniaturisation, allowing total data acquisition to maximise what human operators can be expected to handle at their work-stations. Artificial Intelligence (AI) is becoming the key enabling component in the battle to avoid data-overload, which unless recognised and dealt with in real time can make quick decision-making more difficult . AI is intended to assist decision-making by humans who provide the ultimate control on response actions, but as more unmanned (UAS) platforms are used for ISR missions, and can carry and launch offensive and defensive weapons, the employment of AI technologies is going to increase in importance and usage. It will be challenging for commanders in the field to decide how much fully automated activity can be allowed to dictate battle plans in accordance with the operational terms of engagement. These human-set parameters take into account the need to avoid “blue-on-blue” friendly-fire or mistaken target identification, and a well-trained operator can, in some tactical circumstances, take a quicker and more appropriate decision than a computer, which is only as reliable as the algorithms in its programming. No doubt the arguments over human vs AI in the realms of ISR will continue to be debated as new air platforms emerge onto the market.
A widely used multi-role aircraft type in service today is not one that is usually associated with the ISR mission. The Lockheed C-130 Hercules family is used by most operators as a tactical cargo and troop carrier, flying from short unprepared airstrips as well as conventional runways, but its capacious fuselage can also be fitted out with multiple work-stations and a high volume of electronic equipment. It can be fitted with numerous sensors, pods and aerials on the fuselage and below the wings with its specialist communications allowing for a variety of low and high frequency radio transmitters and receivers, as well as satellite communications. Such Special Mission platforms can operate almost anywhere in the world, from the Arctic to deserts and remote islands, and can provide secure global links with surface ships and submarines. They can also provide long-endurance electronic intelligence-gathering and radio/telephone surveillance and if necessary, jamming and other countermeasures. Most of these operations are clandestine in nature and rarely attract attention, especially as missions are often restricted to night operations or from very remote locations.
The Boeing 737 family of airliners have been developed into military platforms and the P-8A Poseidon has become a popular maritime patrol aircraft, with a sophisticated anti-surface and anti-submarine capability, but is also well-equipped for ISR tasking over land and sea. The multi-role potential, combined with an airframe and engine which has worldwide technical support through the operation of thousands of civil 737 aircraft makes this a very flexible multi-task aircraft, which will no doubt remain in service for decades ahead.
A relatively new multi-role ISR platform is now available from Saab in different versions. The first to emerge is the GlobalEye, based on the Bombardier 6000 airframe, which offers an endurance of around 11 hours. This is already in Middle East service with United Arab Emirates and is fitted with a large fuselage-mounted advanced 360 degree search radar, featuring the latest gallium nitrate technology and optimised for use as an Airborne Early Warning and Control (AEW&C) aircraft. The long-range radar is designed for working closely with air defence and other aircraft, as a force multiplier air superiority asset, but its capability is also applicable for other missions, such as tracking unauthorised surface movements over land and water, and directing aircraft and helicopters as required. Very small targets can be identified and tracked over huge expanses, and there are also electro-optical and infrared sensors mounted in a lower fuselage streamlined turret. The high-speed of this aircraft and very fuel-efficient twin turbofan engines enable rapid transit speeds to and from patrol areas. Another Saab version, also based on the Bombardier 6000, is the Swordfish, which is more specially equipped as a maritime patrol and weapons launcher for anti-submarine and anti-surface attack. It is a new competitor to the Boeing P-8A Poseidon, but is considerably lighter, smaller and has more range. The Bombardier family of business jets includes smaller aircraft, such as the Challenger 350 and Global 5000 and the larger Global 7500, and all are suitable for Special Mission conversions, offering different cabin sizes and endurance. Rival US supplier Gulfstream also offers a growing range of twin jet powered ultra-long range aircraft that can be fitted with military radar and other surveillance sensors and are suitable for surveillance or electronic warfare missions. Brazilian business jet supplier Embraer offers its own family of military Special Mission aircraft, which have been popular as platforms for AEW&C, Surveillance and Reconnaissance and Electronic Warfare.
Airbus has been considering proposals based on a military variant of the A320 which could fulfil a number of operational tasks as a replacement for different and ageing maritime patrol, AEW&C and ISR aircraft. This would be another competitor for the Boeing P-8A, but there are no launch orders at present which would be needed to turn this project study into a firm programme. Airbus is also looking at possible enhancements to its highly regarded, best-selling, A330-based MRTT air tanker. Its large size would enable it to continue to act as a tanker, but also would be fitted with additional radar and other sensors, communications and countermeasure systems and data transfer capabilities to enable it to act as a network command node. With the prospect of a new generation of advanced combat aircraft emerging from the mid-2030s, including the UK’s Tempest and the European FCAS, with accompanying semi-autonomous unmanned weapons delivery air vehicles, the enhanced MRTT/ISR/AEW&C aircraft could become flying headquarters to direct friendly forces across multiple missions. At the lower end of the capability scale, the Airbus family of small twin turboprop military transports can also be adapted for work as ISR/ EW platform aircraft, with the cargo cabin fitted out with display workstations and extra sensors and data processing computers. Italy’s Leonardo has developed the ATR72MP twin turbo-prop airframe as a Special Mission aircraft for the Italian Air Force. This is optimised for the Maritime Patrol role and has a search radar, electro-optical/infrared turret and provision for air-to-surface and anti-submarine weapons. The military configuration is also suitable for other ISR missions.
As large unmanned air platforms continue to mature and grow in capability they are increasingly able to take over some special mission duties from manned aircraft. They have the advantage of being able to remain in the air for extended continuous patrols, well beyond what is possible using conventional specialist aircraft. The UK has used a small fleet of radar-equipped Bombardier jets, known as Sentinels, to provide detailed battlefield surveillance with highly accurate moving target information which could be downloaded to ground stations to direct attacks to identified locations. These aircraft, which have been used over Iraq, Syria and Afghanistan, have now been retired and are being replaced by a mix of unmanned air systems and a cluster of space satellites. Increased use of automated solutions will be a feature of how ISR platforms develop in the future as they offer continuous coverage of huge regions on the ground, or at sea, and eliminate many of the restrictions that apply when using manned aircraft with large on-board teams of specialist crews. The UK is the launch customer for the latest remotely piloted aircraft from General Atomics, known as the MQ-9B Sky Guardian. In RAF service it is called Protector and can fly in controlled air space, with an automated sense and avoid system, alongside civil air traffic and can therefore deploy directly to where it is needed without having to be dismantled and flow out in a large transport aircraft. It looks very similar to the existing MQ-9A Reaper, which is the most widely used large operational unmanned air system, but Protector is only slightly larger, with a bigger wing, and can fly for up to 48 hours and can also carry a 50% larger payload. It has six weapons stations carrying multiple precision missiles or bombs, and will have a reaction time far quicker to what would be the case if the aircraft is only used for surveillance and commanders then have to allocate other air assets to respond.
Multi-role ISR platforms are changing how conflicts are managed and are at the heart of efforts to exploit new systems, weapons and technologies. By using automated solutions with Artificial Intelligence, the role, and high cost, of specialist manned aircraft is now being challenged by a new generation of unmanned platforms. But even this trend is likely over the coming decades to be augmented by space assets in the form of relatively low-cost small satellites.