Definition
The natural tendency of an airplane on the ground to pivot into the wind when a crosswind strikes it from the side, caused by the larger surface area of the vertical tail acting as a wind vane behind the main landing gear pivot point.
Plain English
When wind hits the side of the airplane while it is on the ground, the tail gets pushed downwind, which swings the nose into the wind — just like a weather vane on a roof points into the wind.
Context Anchor
Seen in ground handling discussions for taxiing, takeoff, and landing in crosswind conditions, especially in the Landing Gear chapter when comparing how different gear layouts behave on the runway.
Derivation
From 'weather vane' — the rooftop arrow that pivots to point into the wind. The aviation term keeps the same image: the airplane pivots on its main wheels and the tail swings downwind, leaving the nose pointed into the wind.
Why Pilots Care
Uncorrected weathervaning can cause loss of directional control and runway departure, especially as the aircraft slows and rudder effectiveness decreases.
Analogy
A parked shopping cart in a side wind may swing or roll so its lighter end moves downwind and its front points more into the wind. An airplane on its wheels can show a similar turning tendency when wind pushes on its side.
Grounding Statement
Picture the airplane rolling straight ahead while wind from the left pushes on the tail; the tail moves right, and the nose starts turning left into the wind.
Intuition Check
Do not think of crosswind weathervaning as the airplane simply being blown sideways. The key idea is turning: the airplane’s nose tends to swing into the wind while it is on the ground.
Example Sentence 1
During the landing rollout in a gusty left crosswind, the pilot anticipated weathervaning and held right rudder to keep the airplane tracking down the centerline.
Example Sentence 2
After landing in a left crosswind the nose began weathervaning right as the tailwheel settled, requiring immediate correction to stay on the centerline.