Instrument Landing System Flashcards
Is ILS a Precision or non Precision approach?
Precision
What does ils provide?
Accurate guidance both in Azimuth and elevation
What Conditions is ils designed for?
Low cloud or poor vis
Does ils operate continuously without assistance from ATC?
Yes
What does the localiser transmitter do?
Defined the extended centreline of the instrument runway. And,
Indicates deviation from the optimum lateral approach.
Where is the localiser situated?
Beyond the upwind end of the runway, 300m from the threshold
What does the Glidepath Transmitter do?
Defines the safe descent slope(normally 3 degrees). And, indicates deviation from optimum vertical approach path.
Where is the glidepath transmitter situated?
300m from the landing threshold and offset between 100-200m from the centre line
How many marker beacons are normally installed?
Normally 2 occasionally 3
What do marker beacons do?
Define ranges from the threshold
List the 3 types of marker beacons
Outer marker
Middle marker
Inner marker
How far is the outer marker from the threshold? What Hurtz does it operate on?
3-6nms 400Hz - -
How far is the middle marker from the threshold? What Hurtz does it operate on?
900-1200m from the threshold
1300Hz •-•
How far is the inner marker from the threshold? What Hurtz does it operate on?
300-450m from the threshold.
3000Hz ••••••
Regarding ILS what 4 things does the DME transponder do?
1) Provides Range info instead of marker beacons
2) DME channel frequency paired with localiser, therefore DME automatically tuned when ILS selected
3) Range If zero referenced to runway threshold
4) Accurate only with localiser coverage and up to 25,000ft
What frequency does the localiser operate on?
VHF band 108-112MHz
The localiser radiates two lobes that overlap by 5 degrees. True or False?
True.
When are the two lobes received of equal intensity by the aircraft?
When on The centreline
What is the coverage either side of the centre line out to 17nm?
35 degrees eitherside
What is the centre line coverage either side at 25nms?
10 degrees
What frequency does the glide path operate on?
UHF band
329.3-335MHz
The glidepath radiates 2 loves that overlap by 1 degree.
True or False?
True.