ILS

Question 1

Frequency for the Localizer?

Answer 1

VHF 108 - 112 MHz with odd decimals

Question 2

Frequency for the Glideslope?

Answer 2

UHF 329.15 - 335 MHz

Question 3

Where is the localizer aerial positioned?

Answer 3

300m from the end of the other runway end

Question 4

Where is the glideslope aerial positioned?

Answer 4

300m from the landing threshold and 150m to the side

Question 5

What is the principle of operation for the LOC and GP?

Answer 5

Transmitts two lobes. 90/150 Hz
LOC: 90 is left and 150 is right
GP: 90 is up and 150 is down

Question 6

What is the coverage of the LOC signal in distance and degrees?

Answer 6

35 deg out to 17 nm
10 deg out to 25 nm
7 deg in elevation

Question 7

Max deflection of the localizer needle?

Answer 7

2,5 degrees

Question 8

Describe the signal protection and accuracy checks for the localizer

Answer 8

Signal protection out to 25 nm up to 6’250 ft

Accuracy checked out to 10 nm

Question 9

Coverage of the glideslope?

Answer 9

8 degrees out to 10 nm
Elevation: Lower is 0,45 x GP
Upper is 1,75 x GP

Question 10

Full deflection of the GP needle?

Answer 10

0,7 degrees

Question 11

Where does the false GP beam exist?

Answer 11

At about 6 degrees

Question 12

Describe the LOC/GS monitoring criteria.

What is needed for LOC/GS to be taken off-line?

Answer 12

1. LOC shift more than 35 ft (CAT I), 25 ft (CAT II), 10 ft (CAT III)
2. GP shift: GP x 0,075
3. 50% power reduction

Question 13

What errors are associated with ILS beams?

Answer 13

Bending or scalloping