INSTRUMENT FLIGHT RULES WORKBOOK
Figure 1-22 Radio Magnetic Indicator (RMI)
A course is the intended direction of flight or path over the ground measured in degrees. If an
aircraft is on the 180º radial and is tracking (actual path across the ground) inbound to the
station, the course would be 360º. If that same aircraft were tracking outbound from the station
on the 180º radial, the course would be 180º. When outbound from a station, the course and
radial are the same, and when inbound to a station, the course is the reciprocal of the radial.
Radial and course information are displayed on the RMI and CDI in the T-34C.
RADIO MAGNETIC INDICATOR
The RMI is a navigation instrument that displays aircraft heading and radial information. It
consists of a rotating compass card and two bearing pointers, one for the VOR and one for the
TACAN. The aircraft's magnetic heading is displayed on the compass card beneath the
heading index. The remaining marks around the compass card are called bench markers. Bench
markers divide the compass card into 45º segments and are referred to by their relation to the
heading index (Figure 1-22).
1-28 INTRODUCTION TO AIRBORNE NAVIGATION AND COMMUNICATIONS
EQUIPMENT AND PRINCIPLES OF OPERATION