The Yak-141 (formerly known as Yak-41) was originally developed to replace the Yak-38 for air defence missions aboard the Kiev class carriers/cruisers. These carrier-borne operations are air interception, close air combat and also maritime and ground attacks. The development of the Yak began in 1975, but the prototype did not fly until March 1989. Four prototypes were used for flight testing until 1995. The Yak is a V/STOL (Vertical/Short Take-Off and Landing) airplane, similar to the British Hawker Harrier. The Yak-141 uses the common Soviet V/STOL principle which combines lifts and propulsion jets. Two fuselage mounted lift jets in tandem are mounted behind the cockpit for vertical lift while the cruise power is provided by a single Tumansky R-79 jet engine with afterburning capability for conventional take-off. The Yak is equipped with a digital fly-by-wire system and uses the same multi-mode radar as the MiG-29. The airframe is made of composites materials and aluminum lithium alloys.