Plain English Meaning

The main wheel on the side of the airplane that the wind is blowing toward. If the wind is coming from the left, the right main wheel is the downwind main wheel.

Full Definition

During a crosswind landing, the main landing gear wheel located on the side of the airplane opposite the direction the wind is blowing from. In a sideslip (wing-low) crosswind landing, this wheel touches down after the upwind main wheel.

Context Anchor

Used when describing crosswind landings, especially the touchdown sequence when one main wheel contacts the runway before the other.

Derivation

‘Downwind’ means the side or direction the wind is blowing toward — the side away from the wind source. So the downwind main wheel is simply the main wheel on that side of the airplane.