Geilenkirchen Airbase in western Germany hosts one of the world’s most unusual air forces: fourteen huge aircraft based on the classic four-engine Boeing 707 airliner, each hefting a disc-shaped radar dome resembling a rotating pizza platter.

Amusingly, these jets are officially registered to Luxembourg—a tiny country without any air force. Indeed, the Boeings belong to no one country’s air force, though they are usually commanded in turns by a German and U.S. general.

Instead, the aircraft are owned by NATO as part of the NATO Airborne Early Warning and Control Force (NAEWC), with two squadrons with crews drawn from sixteen member states: Belgium, the Czech Republic, Denmark, Germany, Greece, Hungary, Italy, Luxembourg, the Netherlands, Norway, Poland, Portugal, Romania, Spain, Turkey and the United States. In 2018, Canada announced it would also begin dispatching crews again for NAEWC.

The NAEWC has been operational since June 1982, when it started with eighteen aircraft in three squadrons. Currently, the United States and Germany pay two-thirds of the forces expenses (40 and 25 percent, respectively).

The E-3A AWACS aircraft—aptly named the ‘Sentry’—is designed to provide 360-degree radar coverage in a nearly 250-mile radius, meaning that a single plane flying at 30,000 feet can surveil over 120,000 square miles of airspace. That means just three E-3s can form an unbroken ‘wall’ of radar coverage across Europe.

Because the Sentries are, of course, at an elevated vantage, they’re also better for spotting fast, low-flying aircraft and missiles that ground-based radars would struggle to spot through ground clutter until too late.

Ground-skimming supersonic fighter bombers especially posed a threat during the Cold War when the E-3s were first procured. Today, new threats E-3s may be expected to contend with include drones both small and large, stealth fighters and more sophisticated short and intermediate range ballistic missiles which may see a renaissance in the post-INF treaty era.

NATO has also arranged facilities to forward deploy its E-3s to bases in Konya Turkey; Aktion, Greece, Trapani, Italy and even Ørland, Norway. France and the United Kingdom also sometimes contribute their E-3D and E-3F aircraft to support the force.

The standard sixteen-person crews onboard the NATO Sentries can also coordinate the operations of nearby aircraft in response and patch them in on what it’s seeing. This not only helps fighter pilots ‘see’ more airspace than their onboard radars can cover, but it can sometimes enable them to turn off their active radars to better conceal their location from enemy sensors.

NATO has proactively deployed the E-3s in support of member states. In 1999, they helped coordinate NATO jets that shot down five Serbian MiG-29 fighters during the Kosovo War.

After the 9/11 attacks, NATO E-3s flew patrols off U.S. airspace, and were then sent to Afghanistan to provide flight control support of air operations.

In 2016, they were dispatched to Turkey in 2016 to provide better air defense coverage and also provided surveillance support and flight control for the anti-ISIS coalition.

And recently, NATO’s E-3 fleet has been especially active around Baltics, Polish and Romanian airspace to counter Russia’s own increased air activity as tensions rise between Moscow and NATO.

Time for an Update

The NAEWC’s E-3A aircraft are original production models ordered way back in 1978. However, NATO has upgraded the jets four times between 1988 and 2018, with that last aircraft updated in December 2018 featuring upgrades to analog flight controls with new color digital ‘glass cockpit’ displays and improved flight traffic control capabilities.

In a meeting of foreign ministers in Brussels November 2019, NATO Secretary General Jens Stoltenberg authorized $1 billion more in funding to develop and implement a final update. This is a 33 percent increase over an earlier speculated figure of $750 million

It’s speculated the final upgrade could involve incorporating more internet connectivity, and replacing the aircraft’s dated TF33 turbofans with more modern engines that would allow them to fly higher—thereby extending radar range—and with greater fuel efficiency.

The U.S. Air Force, meanwhile, is implementing a $2.6 billion program to update its thirty-two Sentries aircraft to the new E-3G Block 40/45 standard, featuring open-architecture computers, more reliable electromagnetic sensors, single-track fusion of its multiple sensors, and faster datalinks. However, initial tests revealed several deficiencies, and significant shortcomings in securing the aircraft against cyberwarfare.

One imagines some of the technologies integrated into the E-3G would be appealing to the E-3A improvement project, but given the cost and expense of the E-3G program, NATO might stick to more modest improvements.

The Future of NAEWC

NATO plans to retire the E-3 aircraft in 2035, but doesn’t know what there replacement will look like. It’s moved onto the second phase of a program in which its solicits industrial partners to help develop a conceptual replacement known as the Alliance Future Surveillance and Control (AFSC).

Recently, a study by the Center for Strategic and International Studies listed the U.S. Air Force’s E-3s as one of the types that could potentially be retired early in the next five years to reallocate funding to future capabilities. However, no real U.S. replacement for the E-3 currently exists, so that seems unlikely, at least until some form of new flying long-range aerial radar is ready to take its place.

NATO has only issued extremely vague pronouncement about what it envision for its E-3A replacement, but some of the issues it will seek to address are easy to identify.

For example, Russia and China are both fielding stealth fighters, so future aerial ISR capabilities will likely want low-bandwidth radars and ISR sensors that can track such targets, and more robust streamlined capabilities to forward that data to friendly fighters.

The simplest replacement might simply be to procure, smaller, cheaper and more modern replacements like the Boeing 737-based E-7 Wedgetail, already in use with the Turkish Air Force and on order with the British Royal Air Force.

But NATO might also elect to move away from a traditional AWACS-style solution to a ground-based ‘system of systems’—likely involving aerial drones and ground-based sensors feeding data back to a ground-based command center.

As long-range missiles like the Russian R-37 or Chinese PL-15 pose an increasing threat to non-agile AWACS planes, the idea of an unmanned option also grows more appealing. Keep the human crew on the ground could also reduce operating costs considerably, though of course might make the system vulnerable to disruption of its command and data links.

For the next sixteen years, however, the large manned radar planes will continue to play an important role in NATO’s air defenses—one in which its members states cooperate together upon to an unusual degree.

Sébastien Roblin holds a master’s degree in Conflict Resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing, and refugee resettlement in France and the United States.