Definition
On landing or during taxi, a skid occurs when a tire loses traction with the runway or taxiway surface and slides rather than rolls. It commonly results from excessive braking that locks the wheel, or from braking on a wet, icy, or contaminated surface where available friction is reduced.
Plain English
A skid is when a tire stops rolling and starts sliding across the ground. The wheel is no longer turning freely, so the airplane slides on the rubber instead of rolling on it.
Context Anchor
Seen in landing gear, tire, and brake discussions, especially during touchdown, the landing roll, braking, and taxiing.
Derivation
Skid comes from an old word for a piece of wood used to slide or support something. That origin helps here because the main idea is sliding over a surface instead of moving by normal rolling grip.
Why Pilots Care
Skids let an airplane operate from surfaces where wheels would sink or bog down, but they change ground handling, braking, and directional control requirements.
Analogy
It is like a car tire sliding on a slick road after the brakes are pressed too hard: the wheel is no longer rolling cleanly, so steering and stopping get worse.
Intuition Check
A skid is not just any slide or swerve. In this landing-gear context, it means the tire has lost grip and is sliding instead of rolling.
Example Sentence 1
When the pilot stomped on the brakes during the wet landing, the main tires went into a skid and the aircraft drifted toward the runway edge.
Example Sentence 2
Aircraft equipped with skids require different taxi techniques on pavement to avoid wear.