The delta-shaped wings required Concorde to adopt a higher angle of attack at low speeds than conventional aircraft, but it allowed the formation of large low pressure vortices over the entire upper wing surface, maintaining lift. The normal landing speed was . Because of this high angle, during a landing approach Concorde was on the "back side" of the drag force curve, where raising the nose would increase the rate of descent; the aircraft was thus largely flown on the throttle and was fitted with an autothrottle to reduce the pilot's workload.