The aircraft used reheat (afterburners) only at take-off and to pass through the upper transonic regime to supersonic speeds, between Mach 0.95 and 1.7. Reheat was switched off at all other times. Due to jet engines being highly inefficient at low speeds, Concorde burned of fuel (almost 2% of the maximum fuel load) taxiing to the runway. Fuel used is Jet A-1. Due to the high thrust produced even with the engines at idle, only the two outer engines were run after landing for easier taxiing and less brake pad wear – at low weights after landing, the aircraft would not remain stationary with all four engines idling requiring the brakes to be continuously applied to prevent the aircraft from rolling.