The E-3 Sentry is an airborne early warning and control (AEW&C) aircraft developed by Boeing. Released in the late 1960s, the prototype EC-137 was based on the design of the Boeing 707. This aircraft provides all-weather surveillance, command, and communication for the squadron it will be part of. The E-3A, in particular, was the variant primarily used by the North Atlantic Treaty Organization (NATO). Serving as a support aircraft for the NATO Air Force, about eighteen units of the plane were officially registered to Luxembourg. Powered by the TF33 engine, the E-3A Sentry was equipped with the reliable AN/APY-1radar. This variant eventually became the basis for the E-3B, the KE-3A (which served the Saudi Arabia Air Force), and theJE-3C. As of today, 17 E-3As still serve the NATO and are based at the Geilenkirche Air Base.