The General Dynamics F-111A 'Aardvark' was a supersonic, medium-range interdictor and tactical Attack aircraft that also filled the roles of strategic bomber, aerial reconnaissance, and electronic-warfare aircraft in its various versions. It first entered service in 1967 with the United States Air Force. The F-111 pioneered several technologies for production aircraft, including variable-sweep wings, afterburning turbofan engines, and automated terrain-following radar for low-level, high-speed flight. Its design influenced later variable-sweep wing aircraft, and some of its advanced features have since become commonplace. The F-111 suffered a variety of problems during initial development. Several of its intended roles, such as an aircraft carrier-based naval interceptor with the F-111B, failed to materialize.