Instrument Landing System (ILS) - Ch 6

Question 1

ILS General Info

Answer 1

Precision Instrument

VHF 108-112MHZ with odd numbers after decimal

Question 2

ILS Components

Answer 2

Localiser (lateral)
Markers
Glide Slope (Vertical)
DME co-located (markers if not)

Question 3

Localiser Signal

Answer 3

Low 90MHZ Left
High 150MHZ Right (when right of CL = Fly Left)

When difference: Depth of Modulation = same = you are on CL

Question 4

Coverage

Answer 4

17nm Out 35 degrees

25nm Out 10 degrees

Protected Area

Question 5

Deviation

Answer 5

Each Line = 0.5 degrees

Full Deflection = 2.5 degrees

Question 6

Side Lobes

Answer 6

Transmitted out from main lobes - errors of radar

Question 7

Back Beam

Answer 7

Reverse Indication: only used if programmed into FMC

Question 8

Glide Path General

Answer 8

UHF - 90HZ Lobe (light) High
150HZ Lobe (heavy) low

Question 9

Glide Path Deviation

Answer 9

Deviation Dot = 0.14 degrees

Full deflection = 0.7

Question 10

Glide PAth Antenna

Answer 10

300m from RW threshold

Question 11

Glide Path Coverage

Answer 11

3 degrees is standard

Height = 3x distance

Up to 10 miles

Normal Range 1.35 - 5.25

Intercept from below

Question 12

Glide Path Performance

Answer 12

Within half a scale deflection and remaining within half a scale or abort

Question 13

ILS Frequency

Answer 13

Localiser: VHF 108-111.95MHZ (odd)

Glide Path: UHF 328.6 - 335.4MHZ

Question 14

ROD Calculation

Answer 14

ROD = (Theta x Groundspeed (nm/min)) x 100

Question 15

Height Passing Calculation

Answer 15

= (theta x range from touchdown(nm)) x 100

Question 16

Monitoring

Answer 16

Ground equipment is continuously automatically checking itself,

If fault= remove ident, cease transmission, beam bar + Glide slope disappear, flag warning ATC

Question 17

Interference

Answer 17

Scalloping: night effect - due to changing density

Question 18

LVP Critical Area

Answer 18

Vehicles and AC are excluded from moving

Question 19

LVP Sensitive Area

Answer 19

Vehicle/AC movements are controlled