Figure 1-16. TACAN Characteristics

CHAPTER ONE

INSTRUMENT FLIGHT RULES WORKBOOK

Figure 1-16 TACAN Characteristics

2. Azimuth cone of confusion. The structure of the azimuth cone of confusion over a

TACAN station (Figure 1-16/1-17) is considerably different from other NAVAIDs. The azimuth

cone can be up to 100 or more in width (approximately 15 NM wide at 40,000 feet). Indications

on the aircraft instruments make it appear even wider. Approaching the TACAN station, usable

azimuth information is lost before the actual cone is reached. This is correct even though actual

azimuth unlock is prevented by the memory circuit until after the aircraft has entered the cone.

After the cone is crossed and usable signals are regained, the search cycle extends the unusable

area beyond the actual cone. Only azimuth information is unusable in the cone of confusion;

slant range distance information continues to be displayed on the range indicator.

1-20 INTRODUCTION TO AIRBORNE NAVIGATION AND COMMUNICATIONS

EQUIPMENT AND PRINCIPLES OF OPERATION