Figure 1-1 Limits of LOC Coverage

T-6A INSTRUMENT NAVIGATION

CHAPTER ONE

unless a BC approach procedure is published for that particular

runway and the approach is authorized by ATC.

Identification is in International Morse Code and consists of a three-letter identifier preceded by

the letter I (●●) transmitted on the LOC frequency.

EXAMPLE: I-DIA. The LOC provides course guidance throughout the descent path to the

runway threshold from a distance of 18 NM from the antenna between an altitude of 1000 feet

above the highest terrain along the course line and 4500 feet above the elevation of the antenna

site. Proper off-course indications are provided throughout the following angular areas of the

operational service volume (Figure 1-1):

To 10 either side of the course along a radius of 18 NM from the antenna.

From 10 to 35 degrees either side of the course along a radius of 10 NM.

Unreliable signals may be received outside these areas.

The UHF glideslope transmitter, operating on one of the 40 ILS channels within the frequency

range of 329.15 MHz to 335.00 MHz, radiates its signals in the direction of the LOC front

course. The term glidepath means that portion of the glideslope intersecting the LOC.

LOCALIZER

ANTENNA

NORMAL LIMITS OF LOCALIZER

COVERAGE: THE SAME AREA

APPLIES TO A BACK COURSE

WHEN APPROVED.

Figure 1-1 Limits of LOC Coverage

INTRODUCTION TO NAVIGATION SYSTEMS 1-7