Derived from the famous twin-engine fighter McDonnell Douglas F-4 Phantom II, the RF-4C is a tactical reconnaissance aircraft specifically designed to carry out observation and intelligence-gathering missions, even under difficult and complex flight conditions over enemy territory. Compared to the fighter versions, it was easily identifiable by the configuration of the forward fuselage section, where modern (for the time) photographic and terrain-scanning systems were installed. Used extensively during the Vietnam War, the aircraft was continuously upgraded in its avionics and photographic and data-gathering systems, remaining operational in the United States Air Force and other allied countries until the late 1990s. Its flight performance was notable, with a maximum speed exceeding Mach 2.