Definition
An automatic flight system that controls engine thrust by moving the throttles to maintain a commanded airspeed, Mach number, or thrust setting selected by the pilot. It works alongside the autopilot to manage power during climb, cruise, descent, and approach without the pilot manually adjusting the throttle levers.
Plain English
A system that moves the throttles for you to hold the speed or thrust you set, just like cruise control in a car holds your speed without you pressing the accelerator.
Context Anchor
Seen in aircraft with automatic flight systems, especially during climbs, descents, and instrument approaches where speed and path control are closely managed.
Derivation
From 'auto-' (Greek 'autos' meaning self) and 'throttle' (the lever that controls engine power). Literally 'a self-operating throttle' — the system moves the power levers on the pilot's behalf.
Why Pilots Care
Reduces workload and improves speed precision during climbs, descents, and approaches.
Analogy
Like cruise control in a car: you set the speed, the system manages the throttle, and you stay ready to take over if conditions change.
Intuition Check
Auto-throttle does not mean the airplane is flying itself. It only controls engine power; the pilot or another system must still manage the airplane’s direction and flight path.
Example Sentence 1
After leveling off in cruise, the captain engaged the auto-throttle to hold Mach 0.78.
Example Sentence 2
On final approach the auto-throttle reduced thrust smoothly as the aircraft descended toward the runway.