Wind Triangle for the EASA PPL: Drift and Groundspeed

You draw a neat line on the chart, fly the matching heading, and twenty minutes later the village you expected under the nose slides past well off to your left. The culprit is the wind. The wind triangle is the tool that lets you plan for it: from the track you want and the forecast wind, it gives you the heading to fly, the drift and the groundspeed. In the EASA PPL theory exam, it is a core part of Navigation, tested through calculations and concept questions. This guide gives you the complete method, from mental shortcuts to a worked round-trip example, plus the classic exam traps.

The aircraft moves through the air, and the air moves over the ground. The wind triangle adds the two together. Work out the maximum drift (wind speed × 60 ÷ TAS). The drift is maximum drift × the sine of the wind angle, and the headwind or tailwind component is wind speed × the cosine of that angle. You turn the heading towards the side the wind comes from, and groundspeed is TAS minus the headwind (or plus the tailwind). A round trip in any wind always takes longer than in still air.

What Is the Wind Triangle?

Picture a boat crossing a river. If it points its bow straight at the far bank, the current carries it downstream and it lands lower than planned. To arrive opposite its starting point, it has to aim slightly upstream. An aircraft in a moving air mass does exactly the same thing: the wind plays the part of the current.

The wind triangle, also called the triangle of velocities, links three vectors, each defined by a direction and a speed:

Vector	Direction	Speed
✈️ Air vector (the aircraft through the air)	Heading: where the nose points	True airspeed (TAS)
🌬️ Wind vector (the air over the ground)	The direction the wind blows from	Wind speed
🗺️ Ground vector (the aircraft over the ground)	Track: the path on the chart	Groundspeed (GS)

The ground vector is the sum of the air vector and the wind vector. Know two sides of the triangle and you can find the third. When planning a cross-country, you know the track (drawn on the chart), the TAS (from the flight manual for your chosen power setting) and the forecast wind: what you are looking for is the heading and the groundspeed.

The angle between heading and track is the drift angle. The correction you apply to the heading to cancel it is the wind correction angle (WCA). Drift tells you where the wind would push you; the WCA is how much you turn into wind so it doesn’t.

Indicated Airspeed, True Airspeed and Groundspeed

Three speeds you must not mix up:

Indicated airspeed (IAS) is what the airspeed indicator shows. It depends on air density.
True airspeed (TAS) is the aircraft’s real speed through the air. Higher up, the air is less dense, so TAS becomes greater than IAS. A common rule of thumb is about 2% more per 1,000 ft of altitude.
Groundspeed (GS) is the speed over the ground. It sets your flight time, and therefore your fuel burn.

The wind triangle is always built with TAS, never with IAS.

Track, Heading and Variation: the Full Chain

The wind triangle gives you a true heading. Your compass, however, shows a compass heading. So you apply a chain of corrections, in this order:

Step	How to get it	What it corrects
True track	Measured on the chart from true north	Starting point
True heading	True track ± wind correction angle	Drift caused by the wind
Magnetic heading	True heading − easterly variation (or + westerly)	Magnetic variation
Compass heading	Magnetic heading ± deviation	The aircraft’s own compass error

A few points to remember:

The WCA always turns the heading towards the wind. Wind from the left of track means a heading to the left of track; wind from the right means a heading to the right.
Variation is the angle between true and magnetic north. It changes with location and slowly over the years, so read it from a current chart. The classic memory aid is “variation east, magnetic least; variation west, magnetic best”: subtract easterly variation, add westerly variation.
Deviation is specific to each aircraft and is shown on the compass deviation card in the cockpit.

Where Does Your Wind Come From?

A wind direction always tells you where the wind is blowing from: a wind from 030° blows from the north-east towards the south-west. Its reference depends on the source:

METARs, TAFs and forecast winds aloft: direction relative to true north.
ATIS and ATC: direction relative to magnetic north, like runway numbers.

For planning, you therefore use a true wind with a true track. If you want to brush up on weather reports, our guide on how to read a METAR and TAF walks through every group.

Maximum Drift and the 60 ÷ TAS Factor

Pilots don’t do trigonometry in the cockpit. Two quantities make mental arithmetic easy.

Minutes per Nautical Mile

Dividing 60 by your TAS gives the number of minutes needed to fly one nautical mile:

60 ÷ TAS (TAS in knots)

TAS	Minutes per NM	Still-air time for 30 NM
80 kt	0.75	22.5 min
90 kt	about 0.67	20 min
100 kt	0.6	18 min
120 kt	0.5	15 min

Multiply that factor by a distance and you have the still-air time for a leg.

Maximum Drift

When the wind blows exactly at 90° to your track, drift is as large as it can be. In degrees:

Maximum drift = wind speed × 60 ÷ TAS

With 20 kt of wind and a TAS of 100 kt, maximum drift = 20 × 0.6 = 12°. This is a small-angle approximation and is very accurate as long as the wind is small compared with the TAS: the exact answer is 11.5°, a difference that doesn’t matter in practice.

Drift and Wind Components by Wind Angle

The wind is rarely at exactly 90°. It meets your track at a wind angle: the acute angle between the wind direction and the line of your track. Split the wind into two parts:

the crosswind component, which causes drift: drift = maximum drift × sin(wind angle);
the headwind or tailwind component, which changes groundspeed: wind speed × cos(wind angle).

You don’t need a calculator for the sines. These values are enough:

Wind angle	Sine (crosswind share)	Cosine (head or tail share)
0°	0	1
20°	about 1/3	about 0.95
30°	1/2	about 0.87
45°	about 0.7	about 0.7
60°	about 0.87 (0.9 for mental maths)	1/2
70° and above	almost 1	about 1/3 down to 0
90°	1	0

Notice the symmetry: the cosine of an angle is the sine of its complement. At 30° off the wind, half the wind is crosswind and nearly all the rest is headwind; at 60°, it is the other way round.

Solving the Wind Triangle in 5 Steps

Whether you face an exam question or fill in your navigation log, follow the same order:

Find the wind angle: compare the wind direction with the true track, note the acute angle between them and which side the wind comes from (left or right, ahead or behind).
Work out maximum drift: wind speed × 60 ÷ TAS.
Work out the drift: maximum drift × sin(wind angle).
Find the heading: turn the true track towards the wind by that amount, then apply variation and deviation if needed.
Work out groundspeed and time: GS = TAS − headwind component (or + tailwind component), then time = distance ÷ GS × 60.

Finish with a common-sense check: the heading must be offset towards the side the wind comes from. If the wind is from the right and your heading is left of the track, you have a sign error.

💡 Tip: before any calculation, sketch it in ten seconds. One arrow for the track, one arrow for the wind, and you immediately see which way to correct and whether the wind is mostly ahead or behind. This habit removes most sign errors in the exam.

Worked Example: a Round Trip with a Wind from 030°

Let’s take a fictional training flight: a 45 NM leg on a true track of 090°, then back on 270°. The aircraft flies at a TAS of 100 kt and burns 25 litres per hour. The forecast wind is 030° at 20 kt. Fictional variation: 2° East.

In still air, each leg would take 45 × 0.6 = 27 minutes, so 54 minutes for the round trip.

Outbound (track 090°)

Wind angle: the wind is from 030°, the track is 090°. The angle is 60°, and the wind comes from ahead and to the left.
Maximum drift: 20 × 0.6 = 12°.
Drift: 12 × 0.87 ≈ 10°. With the wind from the left, the aircraft would drift right.
True heading: turn 10° into wind, so 090 − 10 = 080°.
Magnetic heading: easterly variation is subtracted, so 080 − 2 = 078°.
Headwind component: 20 × cos 60° = 10 kt.
Groundspeed: about 100 − 10 = 90 kt.
Time: 45 ÷ 90 × 60 = 30 minutes, three minutes more than in still air.

Inbound (track 270°)

Wind angle: between a wind from 030° and a track of 270° there are 120°. So the wind comes from behind and to the right, 60° off the tail.
Drift: still 10°, but the wind is now from the right, so the aircraft would drift left.
True heading: turn 10° into wind, so 270 + 10 = 280°.
Magnetic heading: 280 − 2 = 278°.
Tailwind component: 10 kt.
Groundspeed: about 100 + 10 = 110 kt.
Time: 45 ÷ 110 × 60 ≈ 24.5 minutes.

The Result, and the Round-Trip Trap

Leg	True heading	Groundspeed	Time	Fuel (25 L/h)
Outbound (track 090°)	080°	90 kt	30 min	12.5 L
Inbound (track 270°)	280°	110 kt	24.5 min	about 10.2 L
Total			54.5 min	about 22.7 L
Still air		100 kt	54 min	22.5 L

The outbound headwind is not cancelled by the inbound tailwind: you spend longer exposed to the unfavourable wind. The difference is small here, but it grows quickly with wind strength. It is a classic exam question: a round trip in any wind always takes longer than the same trip in still air.

A note on precision: the exact vector solution gives 88.5 kt outbound and 108.5 kt inbound. The TAS ± wind component method slightly overestimates groundspeed when drift is large, because part of the TAS is used to hold the track against the crosswind. With a pure 20 kt crosswind, groundspeed drops to about 98 kt even though there is no headwind component at all.

Crosswind Component for Take-Off and Landing

The same sine and cosine split is used on the ground, with a different purpose: checking that the crosswind component suits the aircraft and your own experience.

Example: ATC gives a wind of 300° at 15 kt (magnetic) for runway 27, aligned on 270° magnetic.

Angle between wind and runway: 30°.
Crosswind component: 15 × 0.5 ≈ 7.5 kt, from the right.
Headwind component: 15 × 0.87 ≈ 13 kt.

Then compare the crosswind component with the maximum demonstrated crosswind in your aircraft’s flight manual, and with the personal limits you have agreed with your instructor. Watch out for gusts: redo the calculation with the gust value, not just the mean wind.

Correcting in Flight: the 1 in 60 Rule

Even with careful planning, the actual wind often differs from the forecast. The 1 in 60 rule lets you correct from a simple observation: at 60 NM, a one-degree error puts you about 1 NM off track.

Example: after 30 NM, you find yourself 2 NM right of track, with 30 NM still to go.

Track error: 2 × 60 ÷ 30 = 4°. Your actual track is 4° off the planned one.
Closing angle: 2 × 60 ÷ 30 (distance to go) = 4°.
Total correction: 4 + 4 = 8° left to fly directly to the destination.

The rule rests on the same approximation as maximum drift: for small angles, one degree “equals” one sixtieth of the distance.

Classic EASA PPL Exam Traps

Wind triangle questions are rarely lost on the theory, almost always on a detail:

Reading the wind backwards: a wind from 030° blows from 030°, not towards it.
Correcting the wrong way: the heading always turns towards the wind. The sketch prevents this.
Mixing true and magnetic: true track with true wind, then variation at the end. An ATIS wind is already magnetic.
Using IAS instead of TAS in the wind triangle.
Confusing speeds: groundspeed gives the flight time; TAS builds the triangle.
Assuming the wind cancels out on a round trip: it always lengthens the total time.
Forgetting that a pure crosswind also reduces groundspeed, slightly.
Mixing units: knots and km/h, nautical miles and kilometres. Keep everything in knots and NM.

On exam day, check with your examination centre which equipment is permitted: don’t assume your calculator or flight computer will be accepted without confirming it.

How to Study the Wind Triangle

This topic combines understanding, memorisation and calculation. Work on it in three stages:

Formulas and conventions as flashcards: 60 ÷ TAS, maximum drift, drift, wind components, which way to correct, the track to compass heading chain, sine values. Spaced repetition brings each card back just before you would forget it.
Calculating by hand: redo the example in this article without looking at the answers, then change the wind (from 120°, from 300°, 30 kt) and the TAS.
Exam-style questions: with AltiPrep, you practise Navigation questions with an explanation after every answer, flashcards with spaced repetition and mock exams to track your progress subject by subject.

To see where this topic fits, read our guide to the 9 subjects of the EASA PPL(A) theory exam. Each subject is a separate paper and you need at least 75% on each one; the number of questions and the time allowed are set by your national aviation authority. The full exam rules are in our guide to passing the EASA PPL theory exam.

Are You Ready on This Topic?

You have mastered the wind triangle if you can, without hesitating:

name the three vectors and what each one represents;
work out minutes per NM and a still-air time in your head;
find the drift and the heading for any wind, correcting the right way;
convert a true heading into a magnetic and then a compass heading;
calculate the groundspeed, flight time and fuel for a leg;
work out the crosswind component for a runway;
apply the 1 in 60 rule to correct in flight.

From the Exam Room to the Cockpit

In training, the wind triangle becomes your navigation log: track, forecast wind, heading, groundspeed, estimated time and fuel for every leg. In flight, a timing error at your checkpoints reveals a different headwind or tailwind, and a lateral error reveals a different drift: that is the foundation of dead reckoning.

Key Takeaways

The wind triangle adds the air vector (heading, TAS) and the wind vector to give the ground vector (track, groundspeed).
60 ÷ TAS, maximum drift = wind × 60 ÷ TAS, drift = maximum drift × sine, wind component = wind × cosine: four tools are enough for mental arithmetic.
The heading always turns towards the side the wind comes from.
METAR and TAF winds are true; ATIS and ATC winds are magnetic.
A round trip in any wind always takes longer than in still air, and a pure crosswind slightly reduces groundspeed.

Frequently asked questions

What is the wind triangle?

The wind triangle, or triangle of velocities, links three vectors: the aircraft’s motion through the air (heading and true airspeed), the wind, and the aircraft’s motion over the ground (track and groundspeed). If you know two of them, you can work out the third. In flight planning, you use it to find the heading to fly and the groundspeed from the track you want and the forecast wind.

How do you calculate drift quickly in your head?

First work out the maximum drift: wind speed × 60 ÷ TAS, in degrees. Then multiply it by the sine of the angle between the wind and your track: about half at 30°, 0.7 at 45° and 0.9 at 60°. With 20 kt of wind at 100 kt TAS, maximum drift is 12°, so a wind 30° off the track gives about 6° of drift.

What is the difference between track and heading?

Track is the path the aircraft actually follows over the ground, the line you draw on the chart. Heading is the direction the nose is pointing. With a crosswind they differ by the drift angle, so you fly a heading offset towards the wind to keep the track you planned.

Is the wind in a forecast given in degrees true or magnetic?

Wind directions in METARs, TAFs and forecast winds aloft are given in degrees true. Winds passed by ATC or broadcast on the ATIS are in degrees magnetic, like runway numbers. When solving the wind triangle for planning, use a true wind with a true track and apply variation at the end.

Why does a round trip take longer with wind than without?

Because you spend more time flying against the wind than with it. With a 10 kt headwind out and a 10 kt tailwind back, the minutes lost on the way out are not fully recovered on the way back. A round trip in any wind therefore always takes a little longer, and burns a little more fuel, than the same trip in still air.

Is the wind triangle tested in the EASA PPL theory exam?

Yes. The triangle of velocities, drift, heading and groundspeed are part of the Navigation syllabus of the EASA PPL(A) theory exam. They also come up in Flight Performance and Planning whenever you calculate flight time or fuel with wind. You need at least 75% on each paper to pass it.

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