Definition
Aircraft systems that automatically control engine thrust to maintain a commanded airspeed, Mach number, or thrust setting selected by the pilot or the flight management system. The autothrottle moves the throttle levers as needed to hold the target value during phases such as climb, cruise, descent, and approach, and can be coupled with the autopilot and FMS to manage thrust through a planned flight profile.
Plain English
A system that moves the throttles for you to keep the airplane at the speed or thrust setting you've selected, so you don't have to constantly adjust them by hand.
Context Anchor
Seen in flight management system and autoflight discussions, especially in aircraft where speed and power can be managed automatically during climb, cruise, descent, and approach.
Derivation
Auto' comes from the Greek 'autos', meaning 'self'. 'Throttle' is the engine power control. So an autothrottle is a system that adjusts the throttles by itself.
Why Pilots Care
It lowers workload in busy phases of flight and supports precise speed control for safety and efficiency.
Analogy
Think of cruise control in a car: you set the speed, and the car manages the gas pedal. Autothrottle does the same job for the engines.
Intuition Check
Autothrottle does not mean the airplane is flying itself. It only manages engine power according to the selected mode or command.
Example Sentence 1
After takeoff, the crew engaged the autothrottle to hold climb thrust until reaching cruise altitude.
Example Sentence 2
On final approach the autothrottle systems reduced thrust to maintain the target approach speed.