The US Air Force's strange solution to replacing its E-3 Sentry radar aircraft

Maybe some readers are already sharpening their knives to skin me for posting this photo, but it's not a mistake.

An airman shows the interior of the E-3 Sentry, the sophisticated radar aircraft operated by NATO
E-7A Wedgetail, the new radar aircraft chosen by NATO to replace its E-3 Sentry

The Boeing E-3 Sentry is an airborne warning and control aircraft (AWACS), that is, a radar aircraft. It is based on the Boeing 707 and its most striking feature is the radar housed in a black circular rotordome with a white stripe on the fuselage. This aircraft made its first flight on May 25, 1976, and entered service with the United States Air Force (USAF) in March 1977.

Boeing manufactured a total of 68 E-3 Sentries. This aircraft is currently operated by the USAF (21 units), NATO (18), France (4), Saudi Arabia (5), and Chile (3). The British Royal Air Force (RAF) had seven aircraft, retiring the last three in January 2020 (sold to Chile).

The E-3 is already many years old and today Boeing has a replacement: the E-7 Wedgetail, based on the Boeing 707. So far, 14 E-7s have been manufactured. Of these, 6 are in service in Australia, 4 in South Korea, and 4 in Turkey. The RAF plans to receive 3 E-7s. NATO has chosen the E-7 to replace its E-3s, with a fleet of 6 aircraft. In turn, in March 2023 the USAF signed a contract to purchase 26 E-7s.

Unlike the E-3, the E-7 carries a dorsal fin-mounted MESA (Multifunction Electronically Scanned Array) radar, which has the advantage of less aerodynamic drag than the E-3's rotordome. The E-7's radar has a range of 650 km, compared to 400 km for the E-3. In addition, the E-7 has a flight ceiling of 41,000 feet (12,500 meters) and a range of 6,500 km, compared to the E-3's 42,999 feet (13,106 meters) ceiling and 8,046 km range.

The E-7 Wedgetail seemed like the logical replacement for the E-3 Sentry in the USAF, but there was a surprise. A surprise that is strange and difficult to understand, to tell the truth. Yesterday, the prestigious American defense website The War Zone (TWZ) reported that the USAF has decided to cancel the purchase of the E-7 Wedgetail. Part of the E-3's missions will be assigned to defense satellites, which makes a certain amount of sense.

However, the E-3's work cannot be exclusively entrusted to satellites. There is still a need for an airborne platform equipped with a radar that can take on parts of the early warning missions currently assigned to the E-3. Given that we are talking about an AWACS aircraft based on a commercial airliner, the ideal solution was the E-7. But the USAF had another idea, which is explained by the photo at the top of these lines.

According to TWZ, US Special Assistant to the Secretary of Defense Bryn Woollacott MacDonnell stated yesterday: "We do have in the budget $150 million in FY26 [Fiscal Year 2026] for a joint expeditionary E-2D unit with five dedicated E-2Ds, and the budget also funds for additional E-2Ds to fill the near-term gap at $1.4 billion." The E-2D Advanced Hawkeye is a US Navy airborne early warning (AEW) aircraft. It is the most modern variant of the Grumman E-2 Hawkeye, an aircraft also used by France, Israel, Egypt, Japan, the Republic of China (Taiwan), and Mexico.

The E-2D is a twin-engine turboprop aircraft, so it is slower than the E-3 and E-7: it can reach 648 km/h (400 mph), compared to 854 km/h (530 mph) for the E-2 and 853 km/h (530 mph) for the E-7. The E-2D's ceiling is much lower than its competitors': only 34,777 feet (10,600 meters). Despite this, the E-2D's AN/APY-9 radar has the same range as the E-7's radar: 650 km (400 mi). The biggest drawback is the naval aircraft's range: the E-2D has a range of only 2,708 km (1,700 mi) unrefueled. This would lead to greater dependence on tanker aircraft.

Another major difference between the E-2D and other radar aircraft is that it has a crew of only five: pilot, copilot, and three radar operators. The E-3 has a flight crew of three (pilot, copilot, navigator, and flight engineer) and between 13 and 19 radar operators. The E-7 has a flight crew of two (pilot and copilot) and between eight and ten radar operators.

The E-2D's major drawback is that it can't carry a refresher crew: there's no room on the aircraft. Furthermore, the E-3 and E-7 have a toilet and rest area. These amenities are lacking on the Hawkeye (with one exception: Japan requested that its E-2s be equipped with a toilet and microwave). These shortcomings are understandable for a naval aircraft operating within range of an aircraft carrier, but the E-3 typically performs long-duration missions where such a problem would mean greater crew fatigue.

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Photo: U.S. Air Force / U.S. Navy.