Using the VOR
In review, for VOR radio navigation, there are two components required: the ground transmitter and the airplane recieving equipment. The ground transmitter is located at a specific position on the ground and transmits on an assigned frequency. The airplane equipment includes a reciever with a tuning device and a VOR or omninavigational instrument. The navigation instrument consists of (1) an omnibearing selector (OBS) sometimes referred to as the course selector, (2) a course deviation indicator needle (Left-Right Needle), and (3) a TO-FROM indicator.
The course selector is an azimuth dial that can be rotated to select a desired radial or to determine the radial over which the airplane is flying. In addition, the magnetic course “TO” or “FROM” the station can be determined.
When the course selector is rotated, it moves the course deviation indicator (CDI) or needle to indicate the position of the radial relative to the airplane. If the course selector is rotated until the deviation needle is centered, the radial (magnetic course “FROM” the station) or its reciprocal (magnetic course “TO” the station) can be determined. The course deviation needle will also move to the right or left if the airplane is flown or drifting away from the radial which is set in the course selector.
By centering the needle, the course selector will indicate either the course “FROM” the station or the course “TO” the station. If the flag displays a “TO,” the course shown on the course selector must be flown to the station. (see graphic below) If “FROM” is displayed and the course shown is followed, the airplane will be flown away from the station. (be sure you’re tuned in to the correct frequency… my CFI likes to change the channel when I’m not looking)