Components and Characteristics of the Instrument Landing System (ILS)
T-45A UJPT & E2-C2 INav-04
REFRESHER
Review:
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Your Engineering Lesson Guide for "CNI" System
PRESENTATION
Instrument Landing System (ILS)
NOTE: The ILS information approach system is made up of three
Fig 1: FAA Instrument
functional components; the guidance systems, the range systems, and the
Landing System (ILS)
visual systems. This lesson discusses each of the systems in detail. See
Figure 1 for an ILS pictorial.
I.
Guidance Systems
NOTE: The guidance system of the ILS is made up of two parts, the
localizer transmitter (azimuth information) and the glideslope transmitter
(glidepath information).
A. Localizer - azimuth beacon transmitter is the first half of the ILS
guidance system
1.
Provides precise horizontal (course) guidance information to the
runway centerline by way of a localized navigational beacon to
localizer equipped aircraft within the sensing area of the localizer
beacon signal
2.
Localizer frequency is identified by international Morse code
consisting of a four-letter identifier with the first letter of the
sequence beginning with the letter "I" ( )
3.
Transmitter operates on one of 40 channels specifically set aside
for ILS/LOC
4.
Frequency range is 108.10 to 111.95 MHz (lower end of the VOR
frequency range)
5.
Beacon beam is 5 degrees wide as seen on cockpit instruments
and is approximately 4 times as sensitive as conventional VOR or
TACAN navigation signals
6.
Beam is produced by two overlapping modulated frequencies
a.
Left side of inbound course is a 90-Hz signal and the right side
is a 150-Hz signal
(6-99) Original
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