Once the weather has been checked and some preliminary planning done, it is time to chart the course and determine the data needed to accomplish the flight. The following sections provide a logical sequence to follow in charting the course, filling out a flight log, and filing a flight plan. In the following example, a trip is planned based on the following data and the sectional chart excerpt in Figure 15-25. Route of flight: Chickasha Airport direct to Guthrie Airport; True airspeed (TAS) 115 knots; Winds aloft 360° at 10 knots; Usable fuel 38 gallons; Fuel rate 8 GPH; Deviation +2°.

15.8.1 Steps in Charting the Course #

The following is a suggested sequence for arriving at the pertinent information for the trip. As information is determined, it may be noted as illustrated in the example of a flight log in Figure 15-26.

First draw a line from Chickasha Airport (point A) directly to Guthrie Airport (point F). The course line should begin at the center of the airport of departure and end at the center of the destination airport. If the route is direct, the course line consists of a single straight line; if not direct, it consists of two or more straight line segments.

Appropriate checkpoints should be selected along the route and noted. These should be easy-to-locate points such as large towns, large lakes and rivers, or combinations of recognizable points such as towns with an airport, towns with a network of highways, and railroads entering and departing. Normally, choose only towns indicated by splashes of yellow on the chart. For this trip, four checkpoints have been selected: Checkpoint 1 is a tower located east of the course, further identified by the highway and railroad track which almost parallels the course; Checkpoint 2 is the obstruction just to the west of the course, with Will Rogers World Airport directly to the east; Checkpoint 3 is Wiley Post Airport, which the aircraft should fly directly over; Checkpoint 4 is a private, non-surfaced airport to the west of the course.

The course and areas on either side of the planned route should be checked to determine if there is any type of airspace with which the pilot should be concerned. For this trip, the course passes through a segment of the Class C airspace surrounding Will Rogers World Airport where the floor is 2,500 feet MSL and the ceiling is 5,300 feet MSL (point B), and there is Class D airspace from the surface to 3,800 feet MSL surrounding Wiley Post Airport (point C) during the time the control tower is in operation.

Study the terrain and obstructions along the route to determine the highest and lowest elevations as well as the highest obstruction to be encountered, so that an appropriate altitude conforming to 14 CFR part 91 can be selected. For this trip, the tallest obstruction is part of a series of antennas with a height of 2,749 feet MSL (point D), and the highest elevation, located in the northeast quadrant, is 2,900 feet MSL (point E).

Since the wind is no factor and it is desirable and within the aircraft’s capability to fly above the Class C and D airspace, an altitude of 5,500 feet MSL is chosen; this also gives adequate clearance of all obstructions and conforms to the requirement to fly at an altitude of odd thousand plus 500 feet when on a magnetic course between 0 and 179°. Next, measure the total distance of the course as well as the distance between checkpoints. The total distance is 53 NM.

After determining the distance, the true course should be measured; it is 031°. The WCA can be determined using a flight computer: using a wind of 360° at 10 knots, the WCA is 3° left, which is subtracted from the TC making the TH 28°. Next, locate the isogonic line closest to the route to determine variation; Figure 15-25 shows the variation to be 6.30° E (rounded to 7° E), which is subtracted from the TH, giving an MH of 21°. Next, add 2° to the MH for the deviation correction, giving the compass heading of 23°. Now the GS can be determined; it is 106 knots. Based on this information, the total trip time is 35 minutes (30 minutes plus 5 minutes for climb) with a fuel burn of 4.7 gallons.

As the trip progresses, the pilot can note headings and time and make adjustments in heading, GS, and time.