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).
Plain English
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.
Context Anchor
Seen in ground-based radar navigation, especially when describing radar equipment used by controllers to locate and guide aircraft.
Derivation
Azimuth comes from the Arabic 'as-sumut,' meaning 'the directions,' and has long been used in navigation and astronomy to describe a horizontal angle measured around a reference point. In the cockpit, an azimuth-indicating device is simply an instrument that shows that horizontal angle.
Why Pilots Care
Correct azimuth data lets pilots know their exact lateral position relative to a radar facility and follow precise vectors without visual references.
Analogy
Picture the radar site at the center of a compass face. An azimuth-indicating device shows which direction around that compass face the aircraft is located.
Intuition Check
Do not read azimuth as height or distance. Azimuth is direction around the horizon, such as left, right, or a number of degrees from a reference direction.
Example Sentence 1
The pilot cross-checked the azimuth-indicating devices to confirm the aircraft was tracking the correct radial inbound to the VOR.
Example Sentence 2
During the approach, the controller issued headings based on real-time azimuth data shown on the indicator.