ILS - Instrument Landing System

Question 1

ILS always comprised of 2 systems:

Answer 1

Glide Path Transmitter and a Localizer (LOC) Transmitter

Question 2

ILS installations always include a Final Approach Fix (FAF) which may be one of these:

Answer 2

NDB
DME fix
GNSS waypoint

Question 3

What does Localizer do?

Answer 3

It provides track guidance to the runway centreline.

Question 4

Where is the localizer transmitter located?

Answer 4

At the far end of the runway

Question 5

In what frequency range does the localizer operate?

Answer 5

108.1 to 111.9

Question 6

How wide is the localizer beam?

Answer 6

Between 3° and 6°

Question 7

By how many degrees can the localizer be offset from the runway centerline?

Answer 7

It can be offset by up to 3° and still be considered a straight in approach and will be noted on the approach chart

Question 8

What letter represents the first letter in the Morse code identifier for a localizer?

Answer 8

The letter I (i) if it is straight in and X if it is offset by more than 3°

Question 9

What are Back Course Localizers?

Answer 9

Emit the Localizer signal in the opposite direction. Pilots have to fly these backwards/inversely. They are rare and being phased out in Canada.

Question 10

In which frequency range does the glidepath indicator operate?

Answer 10

UHF range of 329.3 MHz to 335.5 MHz

Question 11

What is the glide path beam width?

Answer 11

1.4°

Question 12

Where is the glide path antenna array located?

Answer 12

Approximately 1000 feet down the runway, and offset by about 400 feet.

Question 13

Glidepath beams can be affected by what?

Answer 13

Excessive snow cover.

Question 14

What is the normal reliable signal coverage for a localizer?

Answer 14

10° within 18 nautical miles

35° within 10 nautical miles