Definition
An automatic braking control system that senses when a wheel is about to stop rotating during braking and momentarily releases brake pressure on that wheel to prevent it from locking up. By cycling brake pressure rapidly, the system maintains the wheel near the point of maximum braking effectiveness while preserving directional control and preventing tire damage on landing rollout.
Plain English
A system that stops the wheels from locking up when you brake hard. If a wheel starts to skid, the system briefly eases off the brake on that wheel so it keeps turning, then reapplies pressure. This gives you the strongest possible braking without the tires sliding.
Context Anchor
You encounter this term during landing rollout, rejected takeoff, and brake system discussions, especially when runway stopping distance matters.
Derivation
"Skid" comes from Old Norse and originally referred to a piece of wood used to slide heavy loads. In aviation, a skid is what happens when a wheel stops rotating and the tire slides along the runway instead of rolling. "Anti-skid" simply means the system works against that sliding condition.
Why Pilots Care
Prevents loss of directional control and reduces stopping distance on wet or slippery runways.
Analogy
It works much like anti-lock brakes in a car: when a wheel is about to slide, the system eases the braking on that wheel so it can roll again.
Intuition Check
Anti-skid does not mean the airplane cannot slide or that the runway has unlimited grip. It only helps prevent wheel slide by adjusting brake pressure.
Example Sentence 1
After touchdown on the wet runway, the captain applied steady brake pressure and let the anti-skid system handle the modulation.
Example Sentence 2
During the rollout the anti-skid system allowed the airplane to decelerate while the pilot maintained directional control with the rudder.