The Hawkeye was evolved as a carrier-borne early-warning aircraft, but is suitable for land-based operations from unimproved fields. The prototype flew for the first time on 21 October 1960, since when four versions have been built.
The E-2A (formerly known as the W2F-1) was the initial production version and flew for the first time on 19 April 1961. Delivery of 62 to the US Navy began on 19 January 1964. The E-2B version, which flew for the first time in February 1969, differs from the E-2A by having a Litton Industries L-304 micro-electronic general-purpose computer and reliability improvements. A retrofit programme updated all operational E-2A to this standard.
The E-2C first flew in January 1971 and 41 had been delivered by the end of 1977. Firm orders exist for a total of 47 aircraft, with procurement of 36 more by the end of 1985. Israel has four and in 1979 Japan released funds for the first four of an eventual total of about 15 for the JASDF. The E-2G has an advanced radar that is capable of detecting airborne targets anywhere in a three-million-cubic-mile surveillance envelope. It first entered service with the US Navy in November 1973 and went to sea on board USS Saratoga in late 1974. A training version is designated TE-2C.
Teams of Hawkeyes are able to maintain patrols on naval task force defence perimeters in all weathers, at an operating height of about 9,150m. They are capable of detecting and assessing any threat from approaching high-Mach-number enemy aircraft over ranges approaching 480km. The radar also monitors movements of enemy ships and land vehicles. It enables each E-2C to track, automatically and simultaneously, more than 250 targets and to control more than 30 airborne interceptions. To make this possible highly sophisticated equipment is carried by the aircraft, including a Randtron Systems AN/APA-171 antenna system housed in a 7.32m diameter saucer-shaped rotodome mounted above the rear fuselage of the aircraft.