The Wind Triangle Explained: Heading, Ground Speed and Drift
An aircraft flies through moving air, so the wind pushes it off its course. The wind triangle is the method that tells you which way to point the nose to track the course you want, and how fast you will actually cover the ground.
The terms
- True airspeed (TAS): your speed through the air.
- Course (track): the path you want over the ground.
- Wind: given as the direction it blows from, and its speed.
- Wind correction angle (WCA): how far you turn into the wind.
- Heading: where the nose points.
- Ground speed (GS): your speed over the ground.
The formulas
- WCA = asin( (wind speed ÷ TAS) × sin(wind direction − course) )
- Heading = course + WCA
- Ground speed = TAS × cos(WCA) − wind speed × cos(wind direction − course)
Worked example
TAS 110 knots, course 090°, wind from 150° at 20 knots. The wind is 60° off the course, from the right. WCA = asin(20 ÷ 110 × 0.866) = about 9.1° to the right. Heading = 099°. Ground speed = 110 × 0.987 − 20 × 0.5 = about 99 knots.
A quick check in the cockpit
Work out the crosswind component of the wind, divide it by your TAS, and multiply by 60. Here 17.3 ÷ 110 × 60 gives about 9.4°, close to the exact 9.1°.
Remember that headings are usually magnetic. Apply magnetic variation to convert your true heading before you fly it.
Open the wind triangle calculator
FAQ
Why does ground speed change with the wind?
A headwind slows your progress over the ground and a tailwind speeds it up. A crosswind also costs a little, because you are pointing partly into it.
Do I turn into the wind or away from it?
Into it. If the wind comes from your right, you point the nose to the right of your course.
More guides
- How to Calculate Crosswind and Headwind Components
- How to Read a METAR: A Plain-English Guide
- How to Read a TAF: Airport Forecasts Explained
- What Is in an ICAO Flight Plan? Every Item Explained
- FAA Part 117 Explained: Flight Time, Duty Period and Rest
- Flight Fuel Planning Explained: Trip, Contingency, Alternate and Reserve
- Density Altitude Explained: How Heat and Height Cut Performance
- How to File a Flight Plan: Steps for Pilots and Dispatchers
- How to Read a NOTAM: ICAO Format Explained
For training and reference only. Check official sources before any real flight.