Plain English Meaning

Instruments that show which direction a navigation station lies in relation to the aircraft, so the pilot can fly toward it, away from it, or along a chosen track.

Full Definition

Cockpit instruments that display direction (bearing) information from a ground-based navigation aid, showing the pilot the horizontal angle to or from a station relative to a reference such as magnetic north or the aircraft heading. Common examples include the VOR course deviation indicator, the radio magnetic indicator (RMI), and the horizontal situation indicator (HSI).