Figure 1-12. Fine Azimuth Pattern

CHAPTER ONE

INSTRUMENT FLIGHT RULES WORKBOOK

antenna rotation (360 divided by nine pulses). The airborne equipment electronically measures

the time lapse between the main reference pulse and the maximum amplitude (signal strength) of

the 15 Hz rotating signal pattern (Figure 1-13). This determines the aircraft's bearing from the

station within a 40 sector. Then, the time lapse between the auxiliary reference pulses and the

maximum amplitude of the 135 Hz signal is measured to determine the aircraft's position within

the 40 sector. The accuracy of this measurement determines the position of the aircraft relative

to the station within plus or minus one degree.

Figure 1-12 Fine Azimuth Pattern

1-16 INTRODUCTION TO AIRBORNE NAVIGATION AND COMMUNICATIONS

EQUIPMENT AND PRINCIPLES OF OPERATION