T-34C AIRCRAFT SYSTEMS FAMILIARIZATION
Figure 12-2 Radio Magnetic Indicator
The heading index is a stationary triangular-shaped reference mark located at the top of the RMI.
The compass card rotates during aircraft heading changes and is graduated in 5º increments.
Aircraft magnetic heading is read under the heading index. A single needle provides bearing
information to a VOR station if the VOR system is in use. A double needle provides bearing
information to a TACAN station if the TACAN is in use. The RMI requires both 26 VAC and
The slaving accessory, located in the avionics compartment, receives inputs from a flux detector
and a directional gyro and sends a heading signal to both RMI cards. The slaving accessory
requires 26 VAC.
The flux detector is a 28-VDC electromagnetic compass located in the port wing tip that sends
magnetic heading signals to the slaving accessory. While accurate, it has an inherent instability
that gives the flux detector a + 2° tolerance.
GYRO AND STANDBY COMPASS SYSTEMS