Definition
A cockpit instrument paired with an automatic direction finder (ADF) that displays the angle between the aircraft's nose and the direction to a tuned non-directional radio beacon (NDB). The needle points toward the station, and the angle is read clockwise from the nose (0°) of the aircraft, regardless of the aircraft's heading.
Plain English
A round dial with a needle that always points at the radio station you're tuned to. The angle the needle shows is measured from straight ahead of the airplane, going clockwise.
Context Anchor
Seen in older radio navigation equipment and in training for navigating to ground radio stations such as non-directional beacons.
Derivation
"Relative" here means measured in relation to something else — in this case, the aircraft's nose, not magnetic north. So the bearing shown is relative to where the airplane is pointing.
Why Pilots Care
Allows immediate determination of the station's position relative to the aircraft heading for intercepting courses or locating the beacon without reference to magnetic north.
Analogy
It is like saying, “The station is at your 2 o’clock.” That tells you where it is compared with the way you are facing, not where it is on a map.
Intuition Check
Do not read “relative” as approximate or uncertain. Here it means measured from the aircraft’s nose instead of measured from north.
Example Sentence 1
With the relative bearing indicator showing 090°, the pilot knew the NDB was directly off the right wing.
Example Sentence 2
The pilot turned left until the relative bearing indicator read zero to fly directly toward the station.