Course/Heading/Track

There are other chart projections available such as the Mercator, a cylindrical chart

projection which uses a cylinder rather than a cone as its developable surface. However,

the disadvantages of this projection (such as variable distance scales and curved great

circle routes) make it awkward for aviation navigation purposes; therefore, it is used less

frequently.

Figure 4.2-4 TPC Chart

COURSE / HEADING / TRACK

Lesson Topic 4.1 introduced direction as one of the four components of DR navigation.

Direction can be further defined by three related terms: course, heading, and track.

Additionally, course and heading can be expressed as true or magnetic, depending on

whether True North or Magnetic North is used as the reference.

Course is the aircraft's intended flight path. When a straight line is drawn from departure

point to destination on a Lambert conformal chart (oriented to True North), the "True

Course" (abbreviated TC), is plotted. Figure 4.2-5 shows and intended flight from the

Mobile TACAN to the Whiting Field TACAN.

Technically, heading is the angular distance of the aircraft's longitudinal axis from a

reference (typically True North or Magnetic North). Generally speaking, heading is direction

the nose of the aircraft is pointed. Figure 4.2-6 shows how True Heading is determined.

The heading of the aircraft will differ from the course in order to compensate for

crosswinds. Lesson Topic 4.5 covers wind in detail.

4.6-24