Heading vs track
You assign an aircraft heading 270. On the radar, it tracks 265. The pilot isn't doing anything wrong. Wind is pushing the aircraft sideways.
Heading
Heading is the direction the aircraft's nose is pointing, measured in degrees from magnetic north. When a controller says "turn left heading 270," the pilot rotates the aircraft until the heading indicator reads 270.
That's it. The pilot controls heading. It's immediate and precise.
Track
Track (or ground track) is the actual path the aircraft follows over the ground. It's what the controller sees on the radar scope - the direction the target is moving.
In calm air, heading and track are the same. Point the nose west and you go west. But add wind and they diverge.
The wind correction angle
Picture an aircraft heading due west (270) in a wind blowing from the northwest. The wind pushes the aircraft slightly south. The nose still points west, but the aircraft drifts to a track of maybe 265 or 260 depending on wind strength.
The difference between heading and track is called the wind correction angle (WCA). A pilot who needs to actually track 270 in that northwest wind would set a heading of 275 or 280 - pointing the nose slightly into the wind to compensate for the drift.
Airline pilots do this automatically. The flight management system calculates the correction and the autopilot holds the desired track. But when ATC assigns a specific heading, the pilot flies that heading, not a corrected track. That's the important distinction.
What controllers see
Controllers see track, not heading. The radar target moves in the direction of the ground track. If you assign heading 360 (due north) and there's a 30-knot wind from the west, the target will drift east. It'll look like the aircraft is heading maybe 005 or 010, even though the pilot is holding 360 exactly.
This matters most when you're vectoring aircraft for approach. You assign a base turn heading to intercept the localizer, and you expect the aircraft to fly a predictable path. In strong crosswinds, the actual path shifts. An aircraft on heading 270 to intercept a runway 28 localizer from the south might need heading 280 in a north wind, or heading 260 in a south wind, to end up in the right place.
Crab angle on approach
Watch an aircraft land in a crosswind sometime. The nose points off to one side while the aircraft moves straight down the runway centerline. That's the crab angle - the pilot is deliberately pointing into the wind to maintain a straight ground track. Just before touchdown, they kick the rudder to align with the runway. It looks dramatic but it's routine.
Practical impact
For en-route work, the heading-track difference rarely causes problems. Aircraft are far apart and small deviations don't matter much.
For approach and departure, it's a different story. When you're threading arrivals onto a final approach course with 3nm spacing, a 5-degree track error compounds quickly. Experienced approach controllers learn to anticipate the wind correction and adjust their vectors.
The wind is usually printed right on the radar scope or available from the METAR. A controller working a runway 27 approach in a 25-knot north wind knows every aircraft on base leg will track south of their assigned heading. They compensate by assigning headings that overshoot slightly.
In radarcontrol.io
Wind affects track realistically in the sim. When you assign a heading, the aircraft flies that magnetic heading, but the ground track shown on radar reflects wind drift. In strong crosswind conditions, you'll see the difference clearly - the target moves in a slightly different direction than you'd expect from the heading alone.
The sim models wind layers at different altitudes, so the correction varies with height. An aircraft descending through different wind layers will see its track shift even without any heading change.
This means your approach vectors need the same wind awareness as real ATC. If the wind is blowing from the north at 30 knots and you're vectoring to a west-facing runway, you'll need to compensate on your base turn headings. It's one of those things that makes working in windy conditions genuinely harder than a calm day.
Related: Ground speed vs indicated airspeed | What is a METAR? | How arrivals are sequenced
Guides: Command reference | Arrivals guide
Play London Center - North Atlantic winds make heading vs track very visible.