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RAF E-3D Sentry

The Future of Air C2 and AEW: E-3 Sentry, Threat Technologies and Future Replacement Options

Justin Bronk
Occasional Papers, 5 June 2017
Air Power and Technology, Military Sciences, Defence Spending, Equipment and Acquisitions, UK, UK Defence
This paper assesses the different options available to the RAF in meeting the government’s objective to extend the crucial air C2 capability provided by the E-3D fleet out to at least 2035. It also explores the trends and emerging capabilities that may well shape the final form of the post-2035 replacement for the E-3 across NATO.

The RAF's six E-3D Sentry Air Battle Management and Surveillance (ABM&S), or AWACS, aircraft perform a large number of functions. However, much-needed modernisation and upgrades to the E-3D fleet have not been carried out, which has resulted in it lagging behind the French and US E-3 fleets in terms of both reliability and mission system capacity. This issue was recognised in the 2015 National Security Strategy and Strategic Defence and Security Review (SDSR), which committed the UK government to upgrade and extend the service life of the E-3D fleet until 2035.

The RAF, as with all European NATO air forces, is struggling to provide adequate combat mass from small fleets of highly capable fast jets with insufficient provision of key enablers such as AWACS aircraft and airborne communications nodes. As such, it is not enough to simply ‘go with the plan’ for ABM&S in general and air C2 in particular if there is a more efficient solution to be had by thinking outside the box.

The RAF’s E-3Ds need a £2-billion CSP both to bring them to rough parity with current US and French standards by the mid-2020s and to stretch the fleet out to 2035 in the process. However, the E-3, even in modernised form, is no longer a cutting-edge ABM&S system in a world where proliferating long-range missile systems and emerging non-Western low-observable fighters can force it to stay hundreds of kilometres from contested airspace, placing a higher premium on BLOS communications capacity rather than onboard sensors.

Even when it is able to operate closer to the battlespace, the AN/APY-1/2 mechanically scanned radar array common to all E-3s has significant inherent limitations in terms of its ability to detect low-observable, very slow moving and hypersonic threats, unlike more modern AESA-equipped AWACS types already in service with the US Navy and various air forces around the world.

An AESA-equipped ABM&S platform with improved communications node capabilities, based on a commercial-derivative airframe, seems a logical alternative option which could provide the RAF with a more capable and efficient alternative to extending the life of the E-3D over the next 20 years.

Such an approach would incur programmatic risk and acquisition and integration costs, but the MoD should examine and weigh these against the expensive work required to extend the E-3D with a view to ensuring the RAF has the best capability possible for the next two decades.

In terms of replacing the E-3 across NATO after 2035, a distributed network of multirole sensor and shooter platforms with ground-based remote C2 provision might well be the option chosen by the US – in particular if the US Navy’s NIFC-CA programme proves successful when fully fielded through the 2020s.

Alternatively, Chinese and other rival powers starting from more of a clean slate in terms of air C2 and wide-area surveillance capabilities may even end up showing the US and its allies the way in this field. However, regardless of the choice made by the US when replacing the E-3, whether it opts for a similar airliner-based AWACS type or a distributed sensor solution with ground-based PED, post-Cold War procurement experience suggests that it will be many years before the chosen solution is brought into service and combat-ready, and will therefore be available to allies.

This has significant implications for the RAF as it seeks to fulfil its air C2 and AEW requirements in the intervening period: whatever platform or configuration of capabilities it chooses will have to serve well beyond 2035 before being replaced.

As such, with state-on-state conflict seemingly a growing possibility and new threat technologies already posing challenges for even the modernised E-3s fleets of the USAF and FAF, the RAF should not be reluctant to consider a more unconventional solution for its ABM&S requirements over the next 20 or so years, instead of simply patching up the E-3D Sentry fleet through a capability sustainment programme in the hope that ‘it will do’ until the US provides a NATO-wide E-3 replacement.

Banner image: An RAF Boeing E3-D Sentry takes off from the Royal International Air Tattoo, Fairford, Gloucestershire. Courtesy of Adrian Pingstone/Wikimedia.

Justin Bronk
Research Fellow, Airpower and Technology

Justin Bronk is the Research Fellow for Airpower and Technology in the Military Sciences team at RUSI. He is also Editor of the... read more

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