Chapter 6 ILS Flashcards
What does the ILS provide guidance in?
Vertical (azimuth) and horizontal
What are ILSs paired with?
DME
What provides range on ILSs?
Marker beacons or DME
What are the frequencies for a localiser and how many channels are there?
108.1-111.95MHz and 40 channels
Odd numbers only
What are the frequencies for the glide path?
328.6-335.4MHz (tune to LOC frequency and GP frequency is paired with it)
What airborne equipment is required for ILS?
Antenna and receiver
What does each dot represent on a CDI when tuned to an ILS?
0.5 degrees
On an HSI what is the degree per dot on the vertical scale?
0.7 degrees
What are the two signals emitted by the localiser?
When looking towards the runway on landing:
- 150Hz on the right
- 90Hz on the left
(Lateral lobes are opposite)
Where is the localiser protection zone?
35 degrees either side of the runway extended centreline and extends out to 17nm
Describe the location of the inner protection zone
10 degrees either side of extended centreline and extends to 25nm
What is the principle of operation of an ILS?
Depth of modulation
What is the max height coverage of an ILS?
6000ft
Where is the antenna location?
300m beyond landing runway threshold and 120m to side of centreline
What frequency is the glidepath?
UHF (328.6Mhz - 335.4Mhz)
What are the locations of the 90Hz and 150Hz lobes on the glidepath?
90Hz = above 150Hz = below
What is the lateral coverage of the ILS?
8 degrees either side of the extended centreline
What is the max number of marker beacons on the ILS?
3
What is the frequency of each marker beacon?
Inner = 3000Hz Middle = 1300Hz Outer = 400Hz
What colour light does the outer marker illuminate?
Blue light
What colour light does the middle marker illuminate?
Amber
What colour light does the inner marker illuminate?
White
What is the vertical range of a marker beacon?
6000ft
What is the range of each marker from the threshold?
Inner = 75-150m Middle = 1050m (+/-150m) Outer = 6.5-11.1km
When flying a back beam approach how can you use the OBI?
You can’t (acts in reverse sense)
How can you use the HSI when flying on the back beam?
Setting the course to QDM gives correct indications
What is the formula for ROD required on a glideslope?
ROD = ((glidepath angle / ground speed) / 60) * 100
What is the formula for height passing?
Height passing = glidepath angle * range from touchdown * 100
What is monitoring accuracy of the localiser for each category?
1 = 35ft for 6 seconds 2 = 25ft for 2 seconds 3 = 10ft for 2 seconds
What is the monitoring accuracy of the glidepath?
Angle change by 0.075 degrees and/or reduction in power exceeds 50%
If a fault is detected what will the system do?
- remove morse code
- cease transmission
- display warning to ATC
- CAT 2 or 3 may allow degrade to a lower category
What are the errors associated with ILS?
- bent beam
- scalloping
What is the critical area?
An area defined where all vehicles and aircraft are excluded during all ILS operations
What is the sensitive area?
An area beyond the critical area where parking and movement of vehicles is strictly controlled during low vis ops
