The first prototype of this single-seat close-support aircraft was flown on May 10, l972, the first production version then being flown on October 21, 1975. A cantilever low-wing monoplane of all metal construction, the A-10A incorporates a tail unit with twin fins and rudders, retractable tricycle landing gear, and two General Electric TF34-GE-100 turbofan engines enclosed in pods, giving the airplane a maximum speed (at sea level) of 439 mph. Intended to have the capability to operate from primitive or unprepared areas, so that it can offer short-term response against enemy vehicles, the A-10A has been specifically designed for this task. A large-area wing gives low-speed maneuverability over the battlefield while carrying heavy loads of weapons, the primary of which is its General Electric GAU-8/A Avenger 30-mm seven-barrel cannon, with a maximum firing rate of 4,200 rounds per minute. Still an important airplane in the USAF inventory, the A-10 is a dedicated battlefield aircraft, able to survive in an environment of intense ground fire and to cripple tanks, vehicles, and artillery with its 30-mm cannon and Maverick missiles. It was a crucial aircraft in Operation Desert Storm. The 600th Thunderbolt II was delivered during l982, this total including 30 combat-ready two-seat trainer aircraft.