Guide for student pilots
How to find the wind correction angle and groundspeed
The wind pushes the aeroplane off the line you drew on the chart. To stay on it you point the nose a little into the wind, and the wind changes how fast you cover the ground. This guide shows a quick mental method that is accurate enough for planning and for checking a calculator, then how to correct for drift in the air.
Written for training. Rules and figures differ between countries and operators, so check them against your own regulations, your school’s manual and your instructor.
1. The words, and which wind to use
- True course (TC). The direction of the leg measured on the chart from true north. It is the line you want to fly over the ground.
- Wind correction angle (WCA). The angle between the course and the heading you must hold to stay on it. The true heading is the course plus or minus the WCA.
- True airspeed (TAS). Your speed through the air. Groundspeed (GS) is your speed over the ground, and the wind is the difference.
- Wind direction is where the wind comes from. A wind of 270 degrees blows from the west, towards the east.
Mind which north the wind is given in. Wind in a METAR, a TAF and a winds-aloft forecast is in degrees true. The wind that a tower or an ATIS gives you for take-off and landing is magnetic. For the planning sums, use the forecast wind at your cruise level, not the surface wind, which is usually weaker and turned to a different direction.
2. The quick method
- Find the angle between the wind and your course. Subtract one from the other and ignore the sign: course 090, wind from 150, angle 60 degrees.
- Split the wind into crosswind and headwind. Multiply the wind speed by the factor in the table below.
- Wind correction angle. WCA in degrees is about 60 × crosswind ÷ TAS. This is the 1-in-60 rule: at 60 NM, one degree of error puts you about 1 NM off track.
- Groundspeed. About TAS minus the headwind component, or plus it if the wind is behind you.
- Heading. Add the WCA to the course if the wind comes from the right, subtract it if the wind comes from the left. You always aim into the wind.
| Angle between wind and course | Crosswind part of the wind | Headwind or tailwind part |
|---|---|---|
| 0° or 180° | 0 | 1 |
| 30° | 0.5 | 0.87 |
| 45° | 0.7 | 0.7 |
| 60° | 0.87 | 0.5 |
| 90° | 1 | 0 |
If the angle is more than 90 degrees the wind is partly behind you. Subtract the angle from 180 and use that row of the table, but treat the along-track part as a tailwind: 120 degrees uses the 60 degree row, with a tailwind.
3. Two worked examples
Example 1: headwind from the right. True course 090, TAS 100 kt, wind 150 degrees at 20 kt. The angle is 60 degrees. Crosswind: 20 × 0.87 = 17 kt. Headwind: 20 × 0.5 = 10 kt. WCA = 60 × 17 ÷ 100 = about 10 degrees. The wind comes from the right, so the true heading is 090 + 10 = 100. Groundspeed is about 100 − 10 = 90 kt. An exact calculation gives 10 degrees and about 88 kt, so the shortcut is within 2 kt. A 60 NM leg takes 41 minutes, against 36 minutes in still air.
Example 2: tailwind from the right. True course 300, TAS 100 kt, wind 060 degrees at 20 kt. The angle is 120 degrees, so count 60 degrees with a tailwind. Crosswind 17 kt, tailwind 10 kt. WCA is again about 10 degrees. Flying north-west, the wind from the north-east is on your right, so the true heading is 300 + 10 = 310. Groundspeed is about 100 + 10 = 110 kt, and the exact figure is about 108.
Check any answer with the picture in your head: wind from the right means heading right of the course, and a headwind means a groundspeed lower than TAS. The wind triangle calculator in the Learning hub shows each step of the exact method, and the lesson on the wind triangle explains why it works.
4. From true heading to compass heading
The wind triangle gives a true heading. To fly it you still apply magnetic variation and then the compass deviation. The steps and the signs are in the guide on how to plan a VFR cross-country flight, and the lesson on time, speed, distance and magnetic variation practises them.
5. In the air: find the real wind and correct for drift
The forecast wind is never exactly right. Fly the planned heading, then check against the ground at a checkpoint. If you are off track, use the same 1-in-60 rule to correct.
- Track error in degrees = distance off track × 60 ÷ distance flown. It tells you how wrong the heading has been.
- Closing angle in degrees = distance off track × 60 ÷ distance to go. It is the extra turn that brings you back to the line at the destination.
- Turn by the sum of the two, towards the track. Example: 3 NM to the right of track after 30 NM, with 60 NM to go. Track error 3 × 60 ÷ 30 = 6 degrees, closing angle 3 × 60 ÷ 60 = 3 degrees, so turn 9 degrees to the left.
- Then re-time. Divide the distance flown by the time to get the real groundspeed, and recalculate your arrival time and fuel. The lesson on fuel, the navigation log and monitoring in flight has the full method.
The rule is accurate for angles up to about 20 degrees. For bigger errors, or when you are not sure where you are, use the procedure your instructor taught you rather than guessing a correction.
6. Mistakes that catch students out
- Using the direction the wind blows to instead of from. Reports and forecasts give the direction it comes from.
- Turning the heading the wrong way. Wind from the right means a heading to the right of the course.
- Mixing true and magnetic directions for the wind and the course.
- Planning with the surface wind instead of the wind at cruise level.
- Using one wind for a long route. Winds change along the route and with height, so work each leg with its own wind.
- Using indicated airspeed in place of true airspeed. At low levels the difference is small, but it grows with height.
Where VectorEFB can help
Build the route on the map, fetch the forecast winds for each leg, and the nav log fills in the true course, wind correction angle, magnetic heading, groundspeed and time for every leg. Work the legs yourself first, then compare. A route with a wind strong enough that the aeroplane cannot hold the track is flagged rather than given a number. See the student page.
VectorEFB is a training and situational awareness aid. It is not certified for navigation. Do the planning yourself first, and use official charts, the AIP, NOTAMs and a proper weather briefing for real flights.
Flying as a licensed pilot? The pilot page shows the same tools.
Next: a first solo cross-country checklist. All guides are listed on the guides page.