Building the navlog by hand and the six columns that keep you found when the GPS quits

A hand-built navigation log uses six core columns—true course, wind correction angle, true heading, magnetic heading, ground speed, and estimated time en route—to give you a complete picture of your cross-country flight before you start the engine. Each number feeds the next in a chain of calculations that accounts for wind, magnetic variation, and compass deviation. Mastering this process is required for your checkride under the Airman Certification Standards (ACS), and it’s the skill that keeps you found when your tablet overheats or your GPS loses signal.

What Is a Navigation Log and Why Does It Matter?

A navlog is a table with a row for each leg of your flight and columns that capture the math required to get from one point to the next. Every value builds on the previous one, and when complete, you have trip fuel, total time en route, and a sequence of checkpoints with planned arrival times.

The navlog does three things no GPS can replicate. It forces you to think through wind, fuel, terrain, and airspace before takeoff. It gives you an in-flight reference that works without electricity. And it builds the mental model of your route that lets you recognize immediately when something doesn’t match expectations.

How Do You Determine True Course?

Start with your sectional chart. Draw a line from your departure airport to your first checkpoint, or checkpoint to checkpoint for multi-leg trips. Lay your plotter on that line, align it with a meridian of longitude, and read the angle. That angle is your true course—the direction of travel measured from true north.

The most common mistake on this step is reading the wrong side of the plotter. Every plotter has two scales: one for eastbound courses and one for westbound. If you drew a line heading northeast and your plotter reads 230 degrees, you used the wrong scale. Always sanity-check the number against the direction of your line on the chart.

How Do You Calculate Wind Correction Angle and Ground Speed?

Pull the winds aloft forecast from the Aviation Weather Center. Select the altitude closest to your planned cruising altitude and note the wind direction and speed.

Use the wind side of your E6B flight computer to solve for two values simultaneously:

• Wind correction angle (WCA): How many degrees left or right you need to crab into the wind to maintain your course
• Ground speed: Your actual speed over the ground after wind effects

Set the wind direction and speed, input your true course and planned true airspeed, and the E6B produces both numbers. Electronic E6Bs accept the same inputs and give the same outputs with less manual manipulation.

How Do You Convert True Heading to Magnetic and Compass Heading?

True heading equals your true course plus (or minus) your wind correction angle. This is the direction your nose must point, measured from true north, to track your desired course.

To get magnetic heading, apply magnetic variation. The isogonic lines on your sectional chart show the difference between true north and magnetic north at your location. Apply the classic memory aid:

• East is least — subtract easterly variation
• West is best — add westerly variation

In the eastern United States, variation might be around 12 degrees west. In western states, it could be 14–15 degrees east.

Finally, apply compass deviation from the compass correction card on your instrument panel. This accounts for errors caused by metals and electrical systems in your specific aircraft. The result is your compass heading—the number you’ll actually read on the instrument.

The full chain: True Course → True Heading → Magnetic Heading → Compass Heading. Four conversions, each representing a real physical force acting on your airplane.

How Do You Calculate Fuel Requirements From the Navlog?

Once you have ground speed for each leg, measure the leg distance on the chart with your plotter. Distance divided by ground speed equals time en route for that leg. On the E6B calculator side, this is a simple ratio: 60 nautical miles at 90 knots = 40 minutes.

Add all leg times for your total estimated time en route, then calculate fuel:

1. Find your fuel burn rate in the Pilot’s Operating Handbook (POH)—a Cessna 172 at 65% power burns roughly 8 gallons per hour
2. Multiply burn rate by total time en route for trip fuel
3. Add required reserves per 14 CFR 91.151:
   • Day VFR: 30 minutes of fuel at normal cruise beyond destination
   • Night VFR: 45 minutes of fuel at normal cruise beyond destination

Base fuel calculations on ground speed, not true airspeed. A strong headwind that cuts your ground speed in half doubles your trip time and fuel burn, even though the engine is doing the same work. This is why the winds aloft forecast is not optional.

What Does a Real Navlog Scenario Look Like?

Consider a 140-nautical-mile cross-country broken into three legs using two visual checkpoints. Winds aloft are 270° at 20 knots, and your true airspeed is 105 knots.

Total time en route: 85 minutes. At 8 GPH, that’s 11.3 gallons for the trip. Add 30-minute day VFR reserve (4 gallons), and you need at least 15.3 gallons total. With 40 usable gallons in a standard Cessna 172, the margins are comfortable.

Now change the scenario: winds from the east at 35 knots on an eastbound course. Ground speed on some legs drops to 70 knots. That same 140-mile trip now takes over two hours and burns 17+ gallons. Still legal, but the margin is significantly thinner—and without running the numbers, you wouldn’t know until you were watching fuel gauges mid-flight.

How Should You Pick and Use Checkpoints in Flight?

Select visual checkpoints that are prominent, easy to identify from altitude, and spaced every 10–15 nautical miles. Good candidates include airports, lakes, highway intersections, towns, and rivers—features that appear on the sectional and are visible from several thousand feet AGL.

Before takeoff, write the cumulative time from departure for each checkpoint on your navlog, not just individual leg times. In flight, one glance at your clock and one glance at the navlog tells you whether you’re ahead or behind schedule—no mental math required while hand-flying in turbulence.

Each checkpoint becomes a decision point: Am I where I should be? Am I on time? Is my fuel where it should be? If any answer is no, the navlog gives you the data to figure out why and adjust.

How Does the Navlog Connect to Filing a Flight Plan?

Nearly every box on the FAA flight plan form pulls directly from your completed navlog: route of flight, estimated time en route, fuel on board, true airspeed. Filing a VFR flight plan for every cross-country means that if you don’t arrive, search and rescue knows where to look. That’s a safety feature that doesn’t depend on battery life.

Key Takeaways

• The six essential navlog columns are true course, wind correction angle, true heading, magnetic heading, ground speed, and estimated time en route—each feeding the next
• Always calculate fuel using ground speed, not true airspeed; headwinds can dramatically increase fuel burn without changing engine performance
• Write cumulative checkpoint times on your navlog before departure for instant in-flight position awareness
• The ACS requires pilotage and dead reckoning proficiency before navigation systems—your examiner will expect a completed navlog with every column filled
• Practice builds speed: the first navlog takes an hour, but after five attempts, you can complete one in 15 minutes