Plain English Meaning

It is the knob on a VOR display that lets the pilot pick which course line, measured outward from the station, the instrument should track and show.

Full Definition

The pilot-operated control on a VOR indicator used to choose which course (radial) to or from a VOR station the instrument will display guidance for. Rotating it changes the selected course, which then drives the course deviation indicator (CDI) and the TO/FROM flag.

Context Anchor

Seen on or near VOR checkpoint signs, where the sign tells the pilot what VOR frequency to use and what to set on the indicator.