The E-2D airborne early warning aircraft, deliveries of which are progressing to the Japan Air Self-Defense Force. Photo: Northrop Grumman

The Japan Air Self-Defense Force (JASDF) is currently introducing the E-2D Advanced Hawkeye as the successor to the E-2C Hawkeye. In light of Japan’s evolving security environment, how can the E-2D contribute to the defense of the nation, and how should it be employed to do so? Drawing upon the latest information provided by Northrop Grumman, this paper examines these questions, incorporating the author’s own perspectives.

From the standpoint of surveillance and command and control in the Pacific theater, the E-2D Advanced Hawkeye possesses the key attributes required to serve as a highly effective asset. Japan is expected to revise its National Security Strategy by the end of this year, and the importance of the Pacific domain will likely be further emphasized. In that sense, the E-2D aligns well with the strategic direction Japan is expected to take.

At the same time, the E-2D offers a high degree of compatibility with existing operational frameworks and systems, allowing Japan to leverage its current infrastructure without the need for major new integration efforts. This means that the time and financial burdens associated with personnel training and the establishment of maintenance infrastructure—both unavoidable when introducing a new aircraft type—can be reduced. Moreover, as a platform common to the U.S. Navy, it enjoys advantages in terms of capability upgrades and interoperability. The aircraft has also been designed to operate effectively in dense threat environments characterized by electronic warfare and cyber competition.

By capitalizing on these strengths, the E-2D can serve not only as a means of strengthening Japan’s national defense, but also as a tool for enhancing cooperation with allies and partners. In other words, its value extends well beyond a simple platform upgrade; it has the potential to play a broader role in shaping Japan’s future defense posture.

E-2Ds deployed with the 601st Flight Squadron at Misawa Air Base. Photo: Toshiharu Suzusaki

Expanding Airspace Coverage Toward the Pacific

During the Cold War, when Japan’s primary concern was responding to airspace incursions in and around its own territory, it was sufficient to focus “northward,” keeping the Soviet Union—the principal threat—in mind. This context helps explain why the E-2C was deployed at Misawa Air Base. Later, as part of a “westward shift,” an E-2 squadron was also stationed at Naha Air Base, but even then operations remained within the confines of the Japanese archipelago.

However, the situation has changed significantly. As the Chinese Navy has expanded its capabilities, acquiring large surface combatants and aircraft carriers capable of operating at extended ranges, it has begun to conduct routine operations in the Pacific.

In fact, Japan’s current Three National Security Documents, formulated in 2022, already highlight the increase in China’s activities in the Pacific and the need to strengthen surveillance and monitoring capabilities in response. Since then, the situation has grown even more severe, with Chinese aircraft carriers now conducting flight operations in the Pacific.

In such an environment, Japan must extend its surveillance and monitoring coverage to the Pacific side. It must monitor not only the movements of naval vessels, but also those of aircraft.

JASDF air defense radars and the movements of Chinese aircraft carriers

Fixed air defense radars(28 sites), mobile air defense radar (5 bases), and the home bases of the E-2D AEW aircraft and E-767 AWACS aircraft are shown. The dashed lines over the southern sea indicate the movements of Chinese Navy aircraft carriers“Liaoning 遼寧”and“Shandong 山東”as disclosed in Japanese Ministry of Defense press releases from 2025–26. Map: GEO+JDN

However, the Pacific side differs from mainland Japan and the Southwest Islands in that there is very little land, while the area requiring coverage is extraordinarily vast.

This scarcity of land places inherent limitations on ground-based surveillance. Indeed, the JASDF has no radar sites in the Ogasawara Islands area, meaning it lacks a means of continuously monitoring airspace from the ground in that region. Even if radar sites were established on remote islands, their coverage would be limited to a radius of several hundred kilometers, leaving significant gaps.

In this context, deploying airborne platforms such as the E-2D as needed is far more effective than relying solely on fixed ground-based radars. There are two primary reasons for this.

First, mounting radar on an aircraft allows it to operate at high altitude, extending its “field of view” beyond the horizon as seen from the ground or sea level. This enables earlier detection of incoming threats, particularly those flying at low altitude.

Second is mobility. Aircraft carrying radar systems can rapidly deploy and reposition, making it possible to send “eyes in the sky” wherever and whenever they are needed. This is especially effective when deploying wide-area surveillance capabilities across the Pacific, where usable land is scarce.

Moreover, the E-2D is not merely an airborne radar platform; it also functions as a “flying command post.” It can deploy both situational awareness and air battle management capabilities to a specific area, effectively providing a localized version of the JADGE (Japan Aerospace Defense Ground Environment) system. This allows it to support timely situational awareness and decision-making for integrated defense operations spanning land, sea, and air domains. In other words, it can deploy not only “eyes,” but also a “brain.”

Enhanced Command and Control Capabilities and Information Sharing Through Data Links

The E-2D retains the same five-person crew as the E-2C: pilot, co-pilot, and three controllers in the rear cabin. In the U.S. Navy, these positions correspond respectively to the Radar Operator (RO) and Weapons System Officer (WSO), the Combat Information Center Officer (CICO), and the Air Control Officer (ACO), though these designations are not used in Japan.

Additionally, the E-2D introduces a 17-inch display at the co-pilot’s station, allowing the co-pilot to assist in control tasks as needed. In practical terms, this is equivalent to adding another controller, making it easier to avoid saturation of the crew’s processing capacity.

Network capabilities have also been enhanced. Like the E-2C, the E-2D supports Link 16 tactical data links, enabling the sharing of radar-derived tracking information with aircraft and ships. Moreover, because Link 16 is a common tactical data link used throughout the Western alliance, it contributes significantly to joint and multinational operations.

In addition, the E-2D’s mission systems are capable of controlling unmanned systems. This opens the possibility of integrating both manned and unmanned aircraft under the centralized control of the E-2D. If fully realized, the E-2D could become a core node for MUM-T (Manned and Unmanned Teaming) operations.

Deployment and Operational Considerations

These capabilities also raise questions regarding optimal deployment and operational posture. At present, E-2 units are based at Misawa (north-oriented) and Naha (west-oriented). However, when considering operations in areas such as Iwo Jima, both locations present significant distance challenges—approximately 1,800 km from Misawa.

One potential approach would be to designate Hamamatsu Air Base—currently home to the E-767—as a Main Operating Base (MOB) for airborne early warning assets, including the E-2D, and deploy them forward to Forward Operating Bases (FOBs) as needed.

The distance from Hamamatsu to Iwo Jima is under 1,200 km, reducing transit time to roughly two-thirds compared to deployment from Misawa. Shorter transit times mean fewer aircraft are required to maintain continuous on-station coverage, resulting in more efficient operations.

This approach is not limited to Iwo Jima. Any island with a suitable airfield could potentially serve as an FOB. Because the E-2D was designed for carrier operations, it can operate from shorter runways and those with lower load-bearing capacity than large AWACS aircraft, expanding the range of available operating locations.

Islands in the Pacific with runways of 1,200 meters or more

Shown are the locations of Misawa 三沢 Air Base (E-2D) and Naha 那覇 Air Base (E-2D), Hamamatsu 浜松 Air Base (E-767), and islands in the Pacific with runways of 1,200 meters or more. Several islands in the Pacific have the potential to serve as operating bases for the E-2D. Map: GEO+JDN

Iwo-to (Iwo Jima 硫黄島), which has a 2,650-meter runway and serves as a training base for the Japan Maritime Self-Defense Force, Japan Air Self-Defense Force, and U.S. Forces Japan. Photo: NASA

Extended Endurance and Improved Habitability

Although the E-2D may be perceived as a small aircraft with limited range due to its carrier-based design, this is not the case. JASDF variants feature a “wet wing” configuration with additional fuel tanks installed within the wings, enabling missions of up to eight hours. (The U.S. Navy, by contrast, addresses endurance requirements by equipping the aircraft with an aerial refueling probe mounted on the nose.)

The ability to remain airborne for extended periods is indispensable for maintaining persistent on-station coverage across the Pacific, where operational areas are vast and available airfields are limited. It allows the aircraft both to operate farther from base and to remain over operational areas for longer periods of time.

Another area improved through operational feedback is habitability. While the aircraft’s physical size remains unchanged, meaning the cabin itself is not larger, the addition of amenities such as a lavatory and microwave oven represents a meaningful enhancement for crews conducting long-duration missions.

Future Potential of the E-2D

Beyond the points discussed above, another important factor is the accumulated experience of the JASDF. Having operated the E-2C for many years, Japan already possesses a substantial foundation in infrastructure, training, maintenance, and operational know-how. The E-2D allows the JASDF to build directly upon this accumulated expertise.

Furthermore, as a platform common to the U.S. Navy, the E-2D will continue to benefit from ongoing capability upgrades in areas such as radar, communications, and command and control. International users of the E-2D can leverage these developments to enhance their own capabilities. Like many modern weapon systems, the E-2D’s mission systems are designed according to an open-architecture philosophy, making it easier to integrate new functions and rapidly expand capabilities.

Northrop Grumman has also emphasized that the program is “built upon decades of cooperative development and mutual trust” and reflects “an ongoing partnership and shared commitment with Japan’s defense industry.” This contributes to confidence not only in future capability sustainment and upgrades, but also in ensuring reliable maintenance and long-term support within Japan.

The E-2D (foreground) and E-2C (background). Deliveries of the E-2D to the JASDF are proceeding on schedule; as of 2026, only a small number of E-2Cs remain in service. Photo: Satoshi Akatsuka