What is a Radio Magnetic Indicator (RMI)?

• A. An electronic instrument that displays airspeed and altitude.
• B. A device that transmits radio signals to determine wind velocity.
• C. An electronic navigation instrument that combines a magnetic compass with an ADF or VOR. The card of the RMI acts as a gyro-stabilized magnetic compass, and shows the magnetic heading the aircraft is flying.
• D. A weather instrument used to observe upper atmosphere.

Answer: (C)

An RMI blends a magnetic heading reference with radio navigation information to give you bearing data to a beacon while showing your heading reference. The gyro-stabilized compass card provides a steady magnetic reference, and a pointer indicates the bearing to the active navigation aid (VOR or ADF/NDB). This lets you determine the direction to fly to reach a VOR, or the direction to a beacon, while still knowing your aircraft’s magnetic heading. In short, it combines orientation with nav signals in one instrument for easier cross-checking of course and heading. The other options describe instruments that measure airspeed/altitude, wind velocity, or weather data, not navigation bearing to a radio navaid.