Relative Bearing Indicator is also described as the fixed-card ADF. Which option correctly names this instrument in the given choices?

• A. Fixed-card ADF
• B. Rotating-card ADF
• C. HSI
• D. VOR

Answer: (A)

The Relative Bearing Indicator shows the direction to the radio beacon (such as an NDB) relative to the aircraft’s nose, and it does so with a fixed compass card. That means the card itself stays stationary while the bearing indication shifts to show where the beacon lies in relation to where you’re pointing. This arrangement is exactly what a fixed-card ADF is designed to display.

The other styles of ADF involve a rotating compass card, which changes with the aircraft’s heading, and the instrument type is not described as a relative bearing indicator. An HSI is a gyro-based instrument that combines heading and course information, not an ADF bearing indicator, and VOR refers to a different navigation source with a separate CDI system.