The recent NATO GlobalEye selection leaves three vital questions unanswered. Will Saab offer a full 360° radar field of regard? How can an aircraft carrying so few operators adequately replace today’s large AWACS platfoms? How many aircraft are required to replace 14 E-3s, and will 10 GlobalEyes be sufficient?
When NATO announced its selection of the Saab GlobalEye at the NATO summit in Ankara on 7 July 2026 the news was largely greeted with equanimity and the proposed replacement of a large Airborne Warning and Control System (AWACS) platform by a converted business jet attracted little comment or controversy. This is perhaps unsurprising, as the new generation of bizjet-based platforms (including the GlobalEye and L3 Harris’ AERIS-X) have capabilities that are broadly equivalent to those of traditional ‘large-aircraft’ AWACS platforms, especially in terms of endurance, range and sensor range. They achieve this while being significantly cheaper than their larger predecessors and competitors, with lower operating, support and sustainment costs.
NATO says the E-3A Sentry AWACS aircraft can detect low-flying targets within 215 nautical miles (400 km) and medium-altitude targets within 280 nautical miles (520 km). Saab claims a range of up to 450 km (240 nm) for the GlobalEye’s Erieye ER airborne early warning (AEW) radar system when flown at an operating altitude of 30,000 ft and 550 km (296 nm) at 35,000 ft. And both types have quoted endurance times of around 11 hours.
Superficially, at least, the two aircraft are thus broadly comparable.
NATO originally purchased 18 E-3A AWACS aircraft, with the first example delivered in January 1982. These E-3As are assigned to the airborne early warning and control (AEW&C) role and have no surface surveillance tasking. This begs the question as to whether Saab has offered the air-to-air-optimised WatchEye configuration previously offered to South Korea or whether the company is pushing the Swing Role Surveillance System (SRSS) configuration used by the United Arab Emirates (UAE) and selected for Sweden.
The SRSS has significant surface surveillance capabilities, largely thanks to the Leonardo Seaspray 7500E active electronically scanned-array (AESA) radar installed under the belly and the undernose electro-optical/infrared (EO/IR) package, which is understood to contain a FLIR Systems Star SAFIRE 380HD sensor. These are capabilities that are not strictly required for the NATO AWACS role, at least insofar as it has been carried out up to now.
Against airborne targets, the Erieye ER radar carried by GlobalEye enjoys a 70% increase in detection range by comparison with earlier versions of the Erieye radar. This has been achieved by the intelligent use of new technology, including gallium nitride transmit/receive modules (TRMs). By comparison, the E-3A has a mechanically scanned ‘old technology’ radar and, although the E-7A’s MESA radar uses an AESA array, the Wedgetail still uses gallium arsenide TRMs with more limited power output.
However, it is a concern that the GlobalEye’s Erieye ER radar only has a field of regard (FoR) of 150° out to each side, leaving 30° ‘blind’ sectors fore and aft. This is believed by some to be a GlobalEye weakness in the air surveillance role, and not without good reason. Nor is such a view controversial; a full 360° FoR was a key user requirement (KUR) when the UK was looking for a new AEW aircraft, for example.
Saab salesmen and marketeers often seek to minimise the importance of a 360° FoR, pointing out that an AEW ‘racetrack’ can be oriented to give the best possible radar coverage along the most likely threat axis.
They are likely to point out that the GlobalEye (supposedly) has full 360° spherical sensor coverage through using its full panoply of different active and passive sensors. By combining the data from all of these sensors in real time operators can, they insist, be provided with “the highest quality picture of the full coverage area”. The salesmen point out that Saab is a leader in sensor fusion and radar technology and has a “long legacy of customers who are using Saab AEW&C capabilities for effective national defence”.
However, what that does not give is a 360° radar picture!
And Saab obviously understands this, as, instead of the SRSS ‘multi-role’ sensors and systems, the company’s offer to South Korea (whose requirement emphasised air-to-air operations) was understood to have been based on a new GlobalEye configuration known internally as WatchEye. This WatchEye ‘fit’ has the usual undernose EO/IR turret and SeaSpray 7500 surface surveillance radar replaced by new X-band AESA radars fore and aft to guarantee a 360° FoR.
This would seem to be the most logical and obvious configuration to offer to several recent/upcoming GlobalEye customers, including France and NATO.
Another KUR for the UK was mission crew size, with the command, control, communications, and intelligence (C3I) element of the AWACS/AEW&C role requiring more operators, since an individual operator can only control a handful of friendly fighters at once. Technology (including AI) can be used to increase ‘capacity’ and to replace some crew roles, but it is generally accepted that ‘more is more’ when it comes to AEW&C crew size. The outgoing E-3 can carry a mission crew of 13-21+, with exact crew counts depending on the specific aircraft variant (eg, E-3A vs E-3B/C) and the mission. For example, the NATO AWACS fleet lists a minimum of 12 mission crew members, while RAF Sentry operations required a standard mission crew of 15.
The E-7A Wedgetail carries a mission crew of 8-12 operators (with 10 being the usual complement).
The GlobalEye usually has just five operator workstations, although some have reported that it could have up to seven, plus four seats in the crew rest area. This helps to explain any scepticism as to how a bizjet platform could adequately replace the E-3A.
It was calculated that it took three E-3As in overlapping orbits to provide complete coverage of Central Europe alone, with one E-3A flying at 30,000 ft (9,144 m) having a field of view of 312,000 km². This drove the original NATO E-3 fleet size of 18 aircraft – and little has changed since then!
The 14 surviving NATO E-3A aircraft are registered in Luxembourg and operated by the NATO Airborne Early Warning and Control Force (NAEW&C Force) – E-3A Component, based at NATO Air Base Geilenkirchen in Germany. Some 20 mixed multi-national crews are provided by 15 of 31 NATO member states.
Three Sentries are based at Geilenkirchen (Germany), with forward operating bases at Trapani/Birgi (Italy), Preveza/Aktion (Greece) and Konya (Turkey). There is a forward operating location at Ørland (Norway).
One NATO E-3A was written off in Greece, while three were retired from service in 2015, 2017 and 2018 as an economy measure, given that the aircraft were approaching an expensive overhaul, and the retired aircraft were used for spares recovery. However, there was no reduction in the required number of orbits and many insiders believed that at least 18 new aircraft should be procured. This reduction in aircraft numbers led to the disbandment of one of three flying squadrons.
Many ask why, if the ‘right’ number of E-3As was 18 (or even 14), how seven E-7As or 10 GlobalEyes could ever be adequate, unless the 10-aircraft fleet will replace only a portion of the NAEW&C Force aircraft, with some NAEW&C Programme Management Organisation (NAPMO) members pursuing separate arrangements.
