How to fill out a VFR nav log
- Draw the course line and measure each true course clockwise from a meridian near the middle of the leg.
- Decode the winds aloft for your altitude. They are true, in knots, so interpolate between the forecast levels.
- Read the true airspeed and fuel flow for your altitude and power from the cruise table.
- Solve the wind triangle for the wind correction angle, true heading and groundspeed.
- Apply variation, then deviation: true heading to magnetic heading to compass heading.
- Work each leg's time and fuel, add the climb from the climb table, then the totals, the reserve and the ETA in UTC.
A worked example
In set HPC234 (ground school), the first leg runs from Callow (DUN) to Kelby, 24 NM on a true course of 277°. At 4,500 ft the forecast for VOW gives 180° at 20 kt at 3,000 ft and 200° at 24 kt at 6,000 ft, so the wind is 190° at 22 kt. With a TAS of 114 kt the wind comes from the left: WCA 11° L, true heading 266°. Variation is 3° E, so the magnetic heading is 263°, and the card's −2° gives a compass heading of 261°. The groundspeed is 111 kt, so the leg takes 13 minutes and 2.0 gal at 9.2 gal/h. Open set HPC234
What each level asks
| Level | The flight | Also |
|---|---|---|
| Student pilot ground school | Three legs from overhead the departure airport, one winds aloft station, one isogonic line | Reserve fuel and the ETA in UTC |
| Private pilot checkride prep | Four legs with a climb after takeoff, two winds aloft stations, two isogonic lines | Taxi fuel, day or night reserve, fuel on board, VFR cruising altitude for the way home |
| Drills | One skill per question | True to compass heading and back, winds aloft codes, interpolation, wind triangle, time and fuel, UTC, reserve |
Questions
How do you convert true course to compass heading?
Work across the log: TC ± WCA = TH ± variation = MH ± deviation = CH. Add a wind correction for wind from the right and subtract it for wind from the left. East variation is subtracted and west variation added (east is least, west is best). Then read the deviation card: for the magnetic heading, steer the compass heading.
How do you read a winds aloft forecast?
Each group is DDff+TT: direction in tens of degrees true, speed in knots, temperature in °C. 2415-03 is 240° at 15 kt, −3 °C. 9900 means light and variable. For 100 to 199 kt, 50 is added to the direction: 7310 is 230° at 110 kt. Above 24,000 ft the minus sign is left out.
Are winds aloft true or magnetic?
True. Winds aloft forecasts and written METAR and TAF winds are given from true north, so they go into the wind triangle with the true course. Winds read out on ATIS and on ASOS or AWOS radio broadcasts are magnetic, like the runway numbers.
How do you work out the wind correction angle without an E6B?
WCA = asin(wind speed × sin(wind direction − TC) ÷ TAS), and GS = TAS × cos(WCA) − wind speed × cos(wind direction − TC). The handbook example: TC 090°, wind 045° at 40 kt, TAS 120 kt gives a WCA of 14° left and a groundspeed of 88 kt.
How much reserve fuel do you need for VFR?
In an airplane, 14 CFR 91.151 asks for enough fuel to reach the first point of intended landing and then fly 30 more minutes at normal cruising speed by day, or 45 minutes at night. Here the reserve is the cruise fuel flow for 30 or 45 minutes.
Which VFR cruising altitude should you plan?
More than 3,000 ft above the surface and below 18,000 ft MSL, 14 CFR 91.159 uses the magnetic course: 0 to 179° takes odd thousands plus 500 (3,500, 5,500, 7,500), and 180 to 359° even thousands plus 500 (4,500, 6,500, 8,500).
Why is my answer marked right when it differs from the key?
An E6B or a plotter is good to about a degree or two, so courses and headings are accepted within 2°, groundspeed within 2 kt and leg times within a minute. Leg times are rounded to the minute and the fuel is worked from the rounded time, as on a paper log.
Sources, checked October 25, 2026: FAA Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25C (2023), chapter 16: variation, deviation card, wind triangle, flight log; Private Pilot Airplane ACS, FAA-S-ACS-6C (PDF): task I.D cross-country planning and area VI navigation; FAA Aviation Weather Handbook, FAA-H-8083-28 (2022, PDF), section 27.2: winds and temperatures aloft; 14 CFR 91.151, fuel for VFR flight; 14 CFR 91.159, VFR cruising altitude.