Home / VFR Academy / Planning
VFR Academy · Planning
VFR navigation: course, wind and variation
From a line on the chart to a flight plan: true and magnetic course, wind correction, magnetic variation in Poland, ground speed, leg time and fuel. With formulas and an example worked out step by step.
Applies to: Poland. Navigation formulas and principles are the same all over the world. The magnetic variation values, transition altitude and examples apply to Poland (WMM 2025 model, AIP Poland of 1 October 2026). Before the flight check the current AIP and the wind forecast.
From a line on the chart to a course
Scope: worldwide · navigation principles, ICAO
VFR navigation starts with a straight line between the route points. For each leg you read two things:
- True course (TC) - the angle of the track line measured clockwise from geographic north, from 000° to 360°. On the chart you measure it with a protractor in the middle of the leg, against the nearest meridian.
- Distance - in nautical miles (NM). 1 NM = 1852 m, and one minute of latitude is exactly 1 NM, so you have a mile scale on every meridian of the chart.
From the course and the wind you then work out the heading - where you point the aircraft's nose to fly along the track line. The next steps are variation and wind.
Magnetic variation in Poland
Applies to: Poland · Source: NOAA World Magnetic Model 2025 · calculated for 2026
The compass shows magnetic north, while the chart is drawn against geographic north. The angle between them is the variation (declination). In Poland it is easterly: magnetic north lies a few degrees east of geographic north, so the magnetic course is smaller than the true course.
| Place | Variation 2026 | Example: TC 090° |
|---|---|---|
| Szczecin | 5.6° E | MC 084° |
| Wroclaw | 5.9° E | MC 084° |
| Krakow | 6.4° E | MC 084° |
| Gdansk | 6.9° E | MC 083° |
| Warsaw | 7.0° E | MC 083° |
| Bialystok | 7.8° E | MC 082° |
Formula · magnetic course
MC = TC - easterly variation · MC = TC + westerly variation
MH = TH - easterly variation
Compass heading: CH = MH ± deviation from the aircraft's deviation card.
Variation changes with place and with time: in Poland it grows by about 0.1° a year. VFR charts mark it with lines of equal variation (isogonals), and the vfrmap.eu map computes it for the middle of each leg from the WMM model. On a route across the whole country the difference reaches 2°, so on long legs take the variation from their middle.
Wind and the wind triangle
Scope: worldwide · navigation principles, ICAO
The aircraft moves relative to the air, and the air relative to the ground. A crosswind drifts the aircraft off the track line, so you have to fly slightly towards the side the wind blows from. Three vectors form the wind triangle:
- true airspeed (TAS) and heading (TH) - the aircraft's movement relative to the air,
- wind (W) - the direction it blows from and its speed,
- ground speed (GS) and track (TC) - the result, i.e. the movement over the ground.
Formula · wind triangle
α = wind direction (where it blows from) - TC
WCA = arcsin(W × sin α / TAS) · TH = TC + WCA
GS = TAS × cos WCA - W × cos α
Quick mental method: WCA ≈ crosswind component × 60 / TAS. At 100 kt TAS and a 20 kt crosswind that is about 12°.
! Watch out for
- The wind in METAR, TAF and winds aloft forecasts is given from geographic north. You therefore work it with the TC and subtract the variation only at the end.
- The wind given by the tower and in the ATIS is magnetic, because it relates to the runway. Do not mix the two.
- Use the wind at the cruise altitude for the calculation, not at the ground: at 3000 ft it is often several dozen degrees different and twice as strong.
Step-by-step example: Modlin - Lodz
Applies to: Poland · variation from WMM 2025 for 2026 · wind assumed for the calculation
A leg from Warszawa-Modlin airport (EPMO) to Lodz (EPLL). The aircraft flies at 100 kt TAS, the wind at the cruise altitude is 270° / 20 kt (from the west, true).
- Course and distance from the chart: TC = 227°, distance 64.0 NM.
- Variation in the middle of the leg: 6.8° E, so MC = 227° - 7° = 220°.
- Wind angle to the track: α = 270° - 227° = 43°. The wind blows from the right, from ahead.
- Correction: WCA = arcsin(20 × sin 43° / 100) = arcsin(0.136) ≈ +8°, i.e. to the right, into the wind. TH = 227° + 8° = 235°.
- Magnetic heading: MH = 235° - 7° = 228°. This is what you set on the compass (corrected for deviation).
- Ground speed: GS = 100 × cos 8° - 20 × cos 43° ≈ 99 - 15 = 84 kt.
- Time: 64.0 / 84 × 60 ≈ 45.5 min.
- Fuel for the leg at 25 l/h: 45.5 / 60 × 25 ≈ 19 l.
Nav log (PLOG)
Applies to: Poland · example with WMM 2025 variation for 2026
You write the results for each leg in the nav log (PLOG). In flight you add the actual times over the points and see straight away whether you are ahead of or behind the plan. You can print the table as a template.
Nav log - example Warsaw - Modlin - Lodz · TAS 100 kt, wind 270°/20 kt
| Leg | TC | Var. | MC | WCA | MH | NM | GS | Time | ETA |
|---|---|---|---|---|---|---|---|---|---|
| EPWA - EPMO | 326° | 7° E | 319° | -10° | 309° | 20.7 | 87 | 14 min | |
| EPMO - EPLL | 227° | 7° E | 220° | +8° | 228° | 64.0 | 84 | 46 min | |
| Total | 84.7 | 60 min | |||||||
A negative correction means wind from the left (heading to the left of the course). You fill in the empty ETA column in flight. Educational material: vfrmap.eu/en/academy/vfr-navigation/.
✓ A quick method: the 1 in 60 rule
If after 60 NM you are 1 NM off track, the course was 1° wrong. In general: track error in degrees ≈ distance off track × 60 / distance flown. After 20 NM and 2 NM off track that is 6°: alter heading by 6° to fly parallel, and by as much again to regain the track over a similar distance.
Time and fuel
Scope: EU · Source: Regulation (EU) 965/2012, Part-NCO (NCO.OP.125)
- You work out the time of each leg from the GS. The sum of the times is the en-route time, to which you add time for take-off, climb and the circuit.
- Trip fuel is the time multiplied by the hourly fuel burn from the aircraft flight manual, with a margin for the climb.
- Final reserve under Part-NCO for aeroplanes: on VFR flights by day at least 30 minutes of flight at normal cruising altitude, at night 45 minutes, and 10 minutes when you take off and land at the same aerodrome and stay in sight of it.
For the example route: 60 min of flight at 25 l/h is 25 l, plus a 30 min reserve (12.5 l) - at least 37.5 l of usable fuel before you add fuel for taxiing, climb and unforeseen route changes. That is the legal minimum, not a plan: agree your own margin with your instructor.
The most common mistakes
- A magnetic wind in a true triangle. An ATIS wind (magnetic) used with the TC gives an error of the whole variation.
- Variation the wrong way. With easterly variation you subtract. "East is least" - easterly variation reduces the course.
- Time from the TAS instead of the GS. With a 20 kt headwind the leg time grows by about 25%.
- The surface wind instead of the wind at altitude. Use the forecast for the cruise altitude.
- No checkpoints. On long legs choose points every 10-15 minutes of flight and compare the times with the plan.
You choose the cruise altitude to fit below the zones and above the terrain - see the article Airspace in Poland for VFR pilots.
Frequently asked questions
How does course differ from magnetic course and from heading?
True course (TC) is the angle of the track line measured from geographic north. Magnetic course (MC) is the same angle measured from magnetic north. Heading (TH or MH) is the direction you point the aircraft's nose after allowing for the wind, so that you fly along the track line.
What is the magnetic variation in Poland?
According to the WMM model, in 2026 the variation in Poland is easterly and ranges from about 5.6° in the west of the country (Szczecin) to about 7.8° in the east (Bialystok), about 7° in Warsaw. It grows by about 0.1° a year. The magnetic course is therefore smaller than the true course by this value.
How do I work out the wind correction?
The wind correction angle (WCA) is the arcsine of the wind speed times the sine of the angle between the wind direction and the course, divided by the true airspeed (TAS). Roughly: the correction in degrees is the crosswind component times 60 divided by the TAS. At 100 kt TAS and a 20 kt crosswind that is about 12°.
Is the wind in a METAR true or magnetic?
In METAR, TAF and winds aloft forecasts the wind direction is given from geographic north (true). The wind given by the tower and in the ATIS is magnetic, because it relates to the runway.
Does an app replace planning the navigation by hand?
No. An app computes courses, corrections and times faster, but the pilot must understand the calculations, check them and be able to navigate with a chart and a watch when the electronics fail. Calculations by hand are also part of the exam.
Sources
- NOAA / BGS, World Magnetic Model 2025 (WMM2025) - ncei.noaa.gov
- Commission Regulation (EU) No 965/2012, Annex VII (Part-NCO), NCO.OP.125 - easa.europa.eu
- ICAO, Annex 3 (Meteorological Service): wind direction in METAR and TAF messages relative to geographic north
Educational material. It does not replace flight training, the current AIP Poland, NOTAM or the regulations. The wind in the example is assumed for the calculation and is not a forecast. Spotted a mistake? Write to info@vfrmap.eu.