The VFR Navigation Log, the Dead-Reckoning Skill Your Examiner Will Ask You to Demonstrate Before You Touch the GPS, and the Checkpoint-to-Checkpoint Planning Process That Still Matters When the Moving Map Goes Dark

A VFR navigation log is a detailed prediction of your entire flight, calculated on the ground before the engine starts. When the actual flight matches that prediction, you know everything is working. When it doesn’t, the nav log tells you something has changed - early enough to respond. GPS tells you where you are right now. The nav log tells you where you expected to be. You need both.

Why Does Your Examiner Want You to Put the iPad Away?

The Private Pilot Airman Certification Standards (ACS) is explicit about what cross-country planning requires: plan the flight using a current sectional chart, measure the course, apply wind correction, calculate estimated time en route, and determine fuel requirements. Watching a student plug a destination into a moving map doesn’t satisfy that standard.

The examiner asking you to set aside the iPad isn’t being hostile. The question exists to find out whether you understand what the moving map is doing underneath the hood - and whether you’ve built the mental model that tells you when something has gone wrong before you stumble into it.

How Do I Choose Checkpoints for My Cross-Country Route?

Start by pulling out the sectional chart and drawing a line from departure to destination. Before calculating a single number, examine the terrain under that corridor. The Maximum Elevation Figures (MEF) - the blue numbers printed inside each quadrant of the chart - show the highest obstacle in each grid square, with a buffer. If the MEF under your route is 9,000 feet, planning a cruise altitude of 8,000 feet is not adequate.

Checkpoints are landmarks along the route that you can positively identify from altitude. Good choices include a distinctive lake, a road intersection at a river crossing, or an isolated town. Avoid checkpoints that could be confused with two other nearby features - at cruise speed you’ll fly past the wrong landmark before you work out that it was the wrong one.

For a 70-nautical-mile flight in a Cessna 172, plan on three to five checkpoints. Place the first one so it appears within eight to twelve minutes of departure. That’s your earliest opportunity to validate that your navigation is on track. Discovering a drift at mile twelve is manageable. Discovering it at mile thirty is a different situation.

Write your checkpoints in order down the left column of the nav log form.

How Do I Calculate True Course, Magnetic Course, and Compass Course?

Use a plotter - a combination straight edge and protractor - aligned with your course line. Read the angle against a true vertical meridian on the chart. That angle, measured clockwise from north, is your true course. Take your time reading it correctly; a ten-degree error here flows downstream into every calculation that follows.

Convert true course to magnetic course using magnetic variation, shown on the sectional as dashed isogonic lines. The memory aid is “east is least, west is best”: subtract east variation, add west variation. In Colorado, variation runs approximately 9–10 degrees east. A true course of 180° with 10° east variation gives a magnetic course of 170°.

Then apply compass deviation - the error your specific aircraft’s compass introduces due to magnetic influences inside the airframe. The compass correction card, that small laminated placard mounted near the compass in every certificated aircraft, lists the correction for each heading. For most light GA airplanes it’s only one or two degrees, but apply it and write down the compass course.

The sequence in order: true course → apply variation → magnetic course → apply deviation → compass course. Work through it in that direction every time.

How Do I Find True Airspeed for Cross-Country Planning?

Indicated airspeed is what the instrument reads. True airspeed (TAS) is your actual speed through the air mass, corrected for air density. At sea level on a standard day the two are nearly identical. At altitude, in thinner air, they can differ by 15–20 knots in the same airplane.

The rule of thumb is roughly a 2% TAS increase for every 1,000 feet of density altitude. For planning purposes, use the Pilot’s Operating Handbook (POH). Find your planned cruise altitude and the expected temperature at that altitude in the cruise performance charts, then read out the TAS for your planned power setting. That’s the number that goes into every calculation from this point.

How Do I Use the E6B Wind Side to Get Wind Correction Angle and Groundspeed?

Pull your Winds and Temperatures Aloft Forecast from aviationweather.gov before planning. This product gives forecast winds at standard altitudes for your route area. Winds aloft are given in true direction (the direction the wind is coming from) and in knots.

The wind side of the E6B is a rotating azimuth disc under a transparent card with a printed grid. Work through it in this sequence:

1. Set the wind direction under the index arrow at the top of the azimuth - rotate the disc until the wind’s origin direction lines up with the index.
2. Mark your wind vector - slide the transparent card so the center grommet sits at a convenient grid point, then mark a pencil dot above the grommet at a distance equal to the wind speed in knots.
3. Rotate the azimuth to place your true course under the index.
4. Slide the transparent card until the pencil dot falls on the arc matching your true airspeed.

Where the dot now sits gives you two answers simultaneously. The groundspeed reads under the center grommet on the speed scale. The wind correction angle is how far left or right of the vertical centerline the dot has moved. Apply that angle to your magnetic course - correct into the wind. Write down both values.

This takes practice. Work through five or six different wind scenarios at home before the lesson where your CFI expects you to demonstrate it. By the tenth repetition, the whole process takes about two minutes per leg.

How Do I Calculate Estimated Time and Fuel Per Leg?

Estimated time per leg is distance divided by groundspeed. A first leg of 22 nautical miles at a groundspeed of 105 knots takes approximately 12.5 minutes.

Fuel burn at cruise is in the POH. A Cessna 172 at normal cruise power burns roughly 8–9 gallons per hour depending on power setting and altitude. At 9 gallons per hour, that 12.5-minute leg burns approximately 1.9 gallons.

Run the same calculation for each leg. Sum the total time and total fuel for the trip. Add approximately one gallon for taxi - startup, run-up, and taxi to the runway.

How Much Fuel Reserve Do I Actually Need?

FAR 91.151 establishes the legal minimums: for daytime VFR, carry enough fuel to reach your first point of intended landing plus 30 minutes at cruise speed. For night VFR, the requirement is 45 minutes. At 9 gallons per hour, the 30-minute daytime minimum equals 4.5 gallons.

Understand clearly: that is a floor, not a plan.

The NTSB publishes accident data annually. Fuel exhaustion and fuel starvation are consistently among the leading causes of general aviation fatalities. When investigators reconstruct those accidents, they don’t find pilots who decided to gamble. They find pilots who made individually small, individually reasonable, optimistic assumptions that compounded into a fatal chain.

Winds stronger than forecast. A hold for traffic at the destination. A small weather deviation that added fifteen miles. A longer taxi than expected at the fuel stop. None of those events, by itself, ends a flight. Put all of them together when you departed with legal minimums, and you’ve consumed every margin you had.

Plan your reserve at a minimum of one full hour at cruise fuel burn. Many experienced cross-country pilots carry an hour and a half and treat landing with less than 45 minutes remaining as a signal that the gap between their plan and the actual flight was larger than it should be.

One additional point: fuel gauges in light aircraft are notoriously unreliable. The regulations require them to read accurately only at empty. At every other fuel state, the gauge can be significantly off in either direction. The only fuel quantity you can fully trust before departure is a visual inspection. Drain the sumps. Check for contamination. Physically look at the fuel level in each tank. If the visual check disagrees with what the lineman said, resolve that discrepancy before starting the engine.

Write your total fuel required on the nav log - trip fuel plus taxi fuel plus reserve - and verify the airplane can carry it. For most training cross-countries in a Cessna 172 it won’t be an issue, but on longer routes in heavier airplanes, run the weight and balance numbers.

What Does a Complete Nav Log Look Like?

A finished nav log captures, for each leg: true course, magnetic course, compass course, true airspeed, wind correction heading, groundspeed, estimated time, and fuel burned. At the bottom: total time, total fuel, and reserve.

When you present this during the oral portion of the practical test, the examiner wants to understand that you know why each column exists. They may ask what happens to your fuel numbers if actual winds are 20% stronger than forecast. They may hand you a different destination and ask you to walk through the process live. They may ask you to identify a suitable en route alternate and explain how you’d divert to it. They’re looking for the understanding behind the numbers, not memorized output.

How Do I Use the Nav Log Once I’m Airborne?

The nav log becomes your reality check in flight. Cross each checkpoint, write down the actual time, and compare it to the estimate.

Within one minute: the flight is tracking. Your calculated groundspeed is close to actual, which means your fuel burn to destination will be close to what you planned.

More than two minutes behind schedule: your actual groundspeed is lower than calculated. The winds were stronger than forecast. Your fuel burn to destination is higher than your nav log shows. Update your numbers forward and make a decision - continue, divert for fuel, or turn back - now, over a known landmark with known fuel remaining.

Ahead of schedule: the wind is working for you. That’s data too.

Every checkpoint is a moment where you compare prediction against reality and decide whether the flight is still going according to plan. That habit of checking, noting, and updating serves you even when every screen in the cockpit is working perfectly. The nav log is how you make sure the surprises stay manageable.

Key Takeaways

• The nav log is a preflight prediction of your entire flight; deviations in flight are your signal to update the plan
• The correct sequence is true course → variation → magnetic course → deviation → compass course; never reverse it
• FAR 91.151’s 30-minute daytime reserve is a legal minimum, not a planning target - carry at least one hour
• Fuel gauges in light aircraft are only required to read accurately at empty; always do a visual check before departure
• Placing your first checkpoint within 8–12 minutes of departure gives you the earliest possible opportunity to catch a navigation error