Boeing E-3 Sentry

The Boeing E-3 Sentry, commonly known as AWACS, is an airborne early warning and control aircraft developed by Boeing as the prime contractor. Derived from the Boeing 707, it provides all-weather surveillance, command, control and communications, and is used by the United States Air Force, NATO, Royal Air Force, French Air Force and Royal Saudi Air Force. The E-3 is distinguished by the distinctive rotating radar dome above the fuselage. Production ended in 1992 after 68 aircraft had been built. In the mid-1960s, the USAF was seeking an aircraft to replace its piston-engined Lockheed EC-121 Warning Star, which had seen service for over a decade. After issuing preliminary development contracts to three companies, the USAF picked Boeing to construct two airframes to test Westinghouse Electric's and Hughes's competing radars. Both radars used Pulse-Doppler technology, with Westinghouse's design emerging as the contract winner. Col. Emmett Virgil Conkling, who was an early participant in radar development in England prior to the official U.S. entry into WWII, retired from his position with the Air Force in the Pentagon and took the position of head of development in Seattle.