Since 2015 the U.S. Navy has been carrying out an ambitious program to upgrade the capabilities of its E-2D Hawkeye turboprop AWACS (Airborne Warning and Control System) aircraft by gradually adding a long list of software upgrades. The basic E-2D had major hardware upgrades, including a glass (flat screen touch displays replacing older analog displays and controls) cockpit, AESA radar and new computers. All the new software capabilities are added in six phases (DSSC 1-6) with the DSSC 4 completed in 2022. When DSSC 6 arrives in about five years the E-2D will have many of the networking and targeting capabilities of the F-35, as well as upgrades to its basic AWACS capabilities. That includes improved stealth detection and targeting capabilities as well as ECM (Electronic Countermeasures) able to cope with the latest enemy jamming and AWACS disruption tools. DSSC also adds improved abilities to detect what is on the ground, because many E-2Ds often operate in coastal waters and have to keep track of what is happening ashore. Many E-2Ds are receiving the aerial refueling upgrade, which costs $2 million for newly built aircraft and $6 million as an upgrade to aircraft built without it. The aerial refueling enables an E-2D to stay in the air up to seven hours.
Not all users have upgraded to E-2D. In 2020 France finally decided to replace its elderly E-2Cs aircraft with new E-2Ds. That left Egypt and Mexico as the only remaining E-2C users. France is the only one, besides the United States, that operates the E-2 from aircraft carriers. All other users operate them solely from land bases. France also went with new aircraft, rather than refurbishing and upgrading their E-3Cs. In part this is because the carrier landings are hard on the structural elements of the aircraft.
But even users of land-based E-3Cs find it more effective to buy new airframes with all the new electronics installed. In 2015 Japan ordered four E-2D aircraft to replace its elderly (since 1987) E-2C aircraft. Given the age of the E-2Cs, Japan considers it more efficient to order newly built E-2Ds than to refurbish the E-2Cs. Japan is not the only E-2 user in the neighborhood. The other user went the upgrade route instead. In 2013 Taiwan received the last two of four E-2K AWACS aircraft from the U.S., where they have been sent for upgrading to the E-2C 2000 standard. The E-2C 2000 entered service in 2005, as an interim upgrade before the E-2D arrived, C 2000 had new engines, AESA phased array radar, new electronics, and many other improvements. The E-2K upgrade cost about $63 million per aircraft. Taiwan bought two E-2Ks new in 2006. The Taiwanese E-2K is very similar to the American E-2C. Taiwan received its first E-2s (four T models) in 1995. Meanwhile American aircraft carriers often operate in and around Japan and each of these ships carries E-2s.
The U.S. Navy received its first E-2D in 2010. This is the latest version of the E-2 that was originally introduced in 1964. The two- engine, 24-ton E-2 was never produced in large quantities, with 320 built so far. Fewer than a hundred E-2s are in use, most of them mealy built E-2Ds or upgrades of relatively new E-2Cs. In 2007 the E-2 fleet reached a milestone of a million flight hours.
The E-2C models began entering service in the 1970s, and are difficult to maintain because of their age. The E-2s always contained a large quantity of the most modern, and failure prone, electronics. Operating mostly off carriers, and thus constantly exposed to corrosive, salty ocean air, the aircraft takes a beating. The five-man crew is mostly concerned with using the large radar carried atop the aircraft and keeping track of friendly, and hostile, aircraft and missiles up to 400 kilometers away.
E-2 can stay in the air for 4-7 hours at a time and cruises at 450 kilometers an hour. Currently, the three "system operators" each use large flat screen displays and many terabytes of disk storage for capturing and comparing data to operate as a sea-going AWACS. It was the navy that developed the AWACS concept at the end of World War II, using Avenger light bombers equipped with radar to control large carrier strikes. The upgraded electronics of the E-2D enable the copilot to also act as a system operator, to quickly reconfigure the displays for the pilot and some of the other system operators. The glass cockpit and new flight software reduces the basic workload of the pilots.
These days each American aircraft carrier has four E-2s, and the U.S. Navy has a total fleet of about 70 E-2s. There are several dozen in service in other countries. About 30 percent of the E-2s ever built are still flying, and the United States expects to keep using them as the E-2D into the 2030s. After that, an unmanned aircraft may replace the E-2 because many DSSC upgrades deal with improved networking security and capabilities. UAV flight control software is increasingly receiving autonomous operation capabilities.
Development and manufacturing of 75 E-2Ds for the U.S. Navy cost about $206 million per aircraft. The E-2D has longer range and more accurate radar, as well as much more efficient and reliable computer systems. Some of the current E-2Cs received some of the electronics improvements, depending on how much longer a particular aircraft would remain in service.