Selecting the Appropriate Charts

STUDENT GUIDE

VISUAL NAVIGATION

6.5.1.2. The low-level training flights are VNAV5 through AVX2, and the flight schedule will

designate the route combinations by both NPA stereo route number (if applicable) and the

syllabus event (VNAV5/VNAV6, VNAV6/VNAV6, etc.)

6.5.2. Selecting the Appropriate Charts

6.5.2.1. As with T-34 VNAV charts, T-1A/T-39 missions also use the TPC1/500,000 scale chart.

However, you may need to tape or glue two or more TPC charts together in order to meet the 20-

NM chart coverage restriction. As with your earlier chart construction, verify your chart editions

using the most current Chart Update Manual (CHUM).

6.5.3. Plotting the Points

6.5.3.1. The AP-1B gives specific coordinates to plot defining the route for filing and course

tolerance purposes. However, these points may or may not have visual significance. Since the

route is flown using visual references as a primary means of navigation, we take the most

visually significant point within NM of the AP-1B coordinates. In order to provide a degree of

standardization between students and instructors, use the points specified in the T-1A/T-39 In-

flight Guide. These provide turn points with proven visual features.

6.5.4. Plotting Course Lines and Radius

6.5.4.1. A course line is the actual path over the ground the aircraft follows when flying the low-

level route. In drawing T-34 VNAV charts, the turn radius was not a consideration due to the

slower airspeed and small turn radius of the T-34. However, in T-1A/T-39 VNAV mission

planning, a turn radius is necessary for every turn of 30 or more.

6.5.4.2. At 300 knots, using 30 angle of bank, the turn radius of most jet aircraft is

approximately 2.5 NM, or a diameter of 5 NM. On a TPC scale chart, this equates to a dime-

sized circle.

6.5.4.3. Use either a dime or the combat plotter to plot the turn radius from a point. Figures 6-3

through 6-6 illustrate the use of the combat plotter. Figure 6-3 shows that from point B to point

C a turn radius is not used since the turn is less than 30. A turn radius is required, however,

from point C to Point D.

6.5.4.4. If using a dime, place the dime face down on the chart with the torch pointed at the turn

point, and perpendicular to the inbound course. Using a pencil, draw the turn radius in using the

dime as a template. With the radius drawn, use a straight edge to draw the course back from the

next point to a point tangent with the turn radius. In other words, with the turn radius drawn, use

the same technique as illustrated in Figure 6-6.

6-5