Definition
The angle between the direction a tire is rolling and the direction it is actually pointed. When a tire is steered or pushed sideways while rolling, it does not track exactly where it is aimed; it tracks slightly off to one side, and that small angular difference is the cornering angle. The tire generates side force in proportion to this angle, which is what allows an aircraft on the ground to turn or resist a crosswind.
Plain English
When a tire is rolling and being pushed sideways at the same time, it actually rolls along a path that is slightly off from the way it is pointed. The small angle between where the tire points and where it really goes is the cornering angle.
Context Anchor
Seen during the landing roll in crosswind conditions, especially when the airplane is slowing down and the tires are carrying more sideways load.
Derivation
The term comes from automotive and tire engineering, where it is also called slip angle. 'Cornering' simply refers to turning a corner; the angle is what makes the tire produce the side force needed to corner. The same physics applies to aircraft tires during the landing roll.
Why Pilots Care
Recognizing how tire cornering force works explains why proper crosswind technique relies on coordinated rudder and aileron inputs rather than brakes alone to keep the airplane tracking straight.
Grounding Statement
Picture rolling a shopping cart straight ahead while someone gently pushes it sideways. It still rolls forward, but its actual path drifts a little off the line the wheels are pointed. That small drift angle is the cornering angle.
Intuition Check
Do not read “cornering angle” as the angle of a turn around a corner. Here it means the sideways angle between the tire’s pointed direction and its actual movement over the runway.
Example Sentence 1
In a strong crosswind rollout, the main tires develop a cornering angle that produces the side force needed to keep the airplane tracking down the centerline.
Example Sentence 2
If the pilot releases aileron input too early the cornering angle grows until the tires reach their limit and the airplane begins to weathervane.