Definition
An automatic control system in which a small input signal is amplified to drive a larger output, with the output continuously monitored and fed back to the input so the system corrects itself until the commanded position or value is reached.
Plain English
A power-assisted device that moves something to a commanded position, then keeps checking and adjusting until it gets there exactly. The system watches its own result and fixes any error automatically.
Context Anchor
Seen in discussions of autopilots, flight-control systems, trim systems, and other aircraft equipment that moves or adjusts something automatically.
Derivation
From Latin servus, meaning 'slave' or 'servant,' combined with 'mechanism.' The idea is a mechanism that serves a command — it does the heavy work but follows orders precisely.
Why Pilots Care
Enables precise, low-effort control of heavy surfaces and allows autopilots to fly the aircraft.
Analogy
Like cruise control in a car. You set a speed, and the system constantly compares actual speed to the set speed, adding or easing throttle to close the gap.
Intuition Check
A servomechanism is not just any motor. The key idea is correction: it uses the actual result to keep adjusting toward the commanded result.
Example Sentence 1
When the pilot dialed in a new heading, the autopilot servomechanism turned the ailerons until the aircraft settled on the commanded heading.
Example Sentence 2
During the check, each servomechanism responded smoothly to the control inputs from the cockpit.