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Radio Magnetic Indicator (RMI) (ID-250/ARN)

The indicator marked “RADIO MAGNETIC INDICATOR”, located on the pilot’s side of the instrument panel, provides the pilots with magnetic heading from the GHARS and visual indication of bearing to a selected station or navigation beacon. The indicator (Figure 1-11-10) consists of a compass card numerically marked in 30 degree increments and linear markings in 2 degree increments, a fixed index, a single-barred pointer, numbered 1, and a doublebarred pointer, numbered 2. The indicator functions are as follows:

a. Compass Card. The azimuth scale, coupled to the GHARS, rotates in the face of the indicator and indicates the magnetic heading of the helicopter against the fixed index.

b. Fixed Index. The fixed index is located at the top of the instrument.

c. Number 1 Pointer. The number 1 singlebarred pointer indicates the relative bearing of a transmitting station received by the low frequency automatic direction finder when the function selector on the LF/ADF control panel is in COMP or LOOP position.

d. Number 2 Pointer. The number 2 doublebarred pointer indicates the magnetic bearing of a station, determined by the TACAN or VOR navigation set.

Figure 1-11-10 Radio Magnetic Indicator