Determine where your flight departure and destination will be. Open up the proper Federal Aviation Administration sectional chart to locate those points on the map.
Lay the aviation plotter flat on the map. Using the plotter like a ruler, draw a straight line with your pencil between the middle of your departure and destination airports.
Determine the course of your flight. Look on the sectional map for a longitudinal line, which runs vertically on your map, that is approximately half way between your departure and destination airports and crosses the straight line you drew in step two. Use your pencil to make a dot where the flight path and line of longitude intersect.
Place the small hole, which is called a grommet, at the place of the half circle connected to the aviation plotter, which is called a directional scale, directly over the dot you made on the sectional map in step three. While keeping the grommet over your dot, line up the aviation plotter along the flight path line you previously drew on the map.
Estimate the true course heading you will be traveling at with the directional scale that is attached to the aviation plotter. Course headings number from 0 to 360, depending on which direction you are traveling. A northern course heading would be zero, eastern travel would be 90, southern flights have a heading of 180 and western flights go at a heading of 270. For example, if flying in a southwestern direction, the flight heading would be approximately 225.
Write the estimated course heading down next to either your departure airport or arrival airport, whichever you prefer, on the sectional map to have as a reference while you are in flight.
Measure the number of nautical miles of your flight path, using the side of the aviation plotter that is opposite the directional scale. The number of nautical miles between your departure and destination points will determine how much fuel your aircraft needs and how much weight the plane can carry. Write the calculated number of nautical miles below the flight course number on your sectional map to have as a reference while you are in flight.
