Figure 1-23. RMI Example A and Example B

INSTRUMENT FLIGHT RULES WORKBOOK

CHAPTER ONE

NOTE

Although the compass card appears to rotate when the aircraft is

turning, it is actually the aircraft turning around the card. When

making a right turn, the card appears to rotate to the left and to the

right for a left turn. Headings will increase numerically when

turning right and decrease when turning left.

The TACAN, or No. 2 needle on the RMI, is used to display radial information from a TACAN

navigation facility. The aircraft's TACAN receiver electronically measures the magnetic bearing

from the station. The head of the TACAN needle indicates the magnetic course to the facility,

and the tail indicates the magnetic bearing from the facility. Remember that a magnetic bearing

from a facility is the definition of a radial, so the tail of the TACAN needle will always indicate

the radial the aircraft is on. Use the TACAN needle when referring to the following examples

(Figure 1-23).

Figure 1-23 RMI Example A and Example B

In example A, the aircraft is on the 250 radial. The magnetic course to the facility is 070. A

turn to a magnetic heading of 070, placing the head of the TACAN needle at the top of the RMI,

will take the aircraft to the facility. In example B, the magnetic course to the facility is 220. The

aircraft is on the 040 radial and heading 180 magnetic.

The VOR needle on the RMI is used to display radial information from a VOR facility. The

head of the VOR needle indicates the magnetic course to the VOR station and the tail indicates

the radial from the VOR station.

INTRODUCTION TO AIRBORNE NAVIGATION AND COMMUNICATIONS

EQUIPMENT AND PRINCIPLES OF OPERATION 1-29