Definition

An Automatic Throttle, generally referred to in aviation as autothrottle or autothrust (depending upon manufacturer), is an electronic or electro-mechanical device which enables a pilot to control the thrust/power setting of the aircraft engines by selection of a specific flight profile, or parameter, rather than by controlling fuel flow via manual manipulation of the thrust/power levers.

More specifically, autothrottle systems refer to designs like the ones found on Boeing and Embraer aircraft. When the system is armed and the pilot advances the thrust levers beyond a certain point, the autothrottle system engages and adjusts power as required by flight parameters. The electromechanical system moves the thrust levers automatically as the need for power changes.