Definition
A control function within an autopilot or stability augmentation system that senses the rate at which the aircraft is moving about an axis (pitch, roll, or yaw) and applies an opposing control input proportional to that rate, reducing oscillations and smoothing the aircraft's response.
Plain English
It is the autopilot's way of pushing back against how fast the aircraft is rotating, so motions like pitching, rolling, or yawing settle down quickly instead of swinging back and forth.
Context Anchor
Seen in autopilot, stability, and automatic flight control system discussions, especially when describing how the system smooths aircraft motion.
Derivation
Rate refers to how fast something is changing (degrees per second of pitch, roll, or yaw). Damping comes from the idea of damping out a vibration -- reducing its size each cycle until it dies away. Combined, rate damping means using the speed of motion to push back against and quiet that motion.
Why Pilots Care
Without effective rate damping, an aircraft can develop persistent oscillations that increase pilot workload and reduce passenger comfort.
Analogy
Think of the shock absorbers on a car. The springs hold the car up, but the shocks resist how fast the car bounces -- so after a bump, the body settles instead of bouncing repeatedly. Rate damping does the same job for an aircraft's motion about its axes.
Grounding Statement
If the airplane starts rotating too quickly, rate damping works against that rotation to settle it down.
Intuition Check
Rate damping does not mean slowing the airplane’s forward speed. It means reducing how fast the airplane is rotating or changing attitude.
Example Sentence 1
The yaw damper provides rate damping about the vertical axis, suppressing Dutch roll tendencies at cruise altitude.
Example Sentence 2
Pitch rate damping allows the autopilot to make smooth corrections without overshooting the selected altitude.