Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Radio Navigation > ILS > Flashcards

ILS Flashcards

1
Q

ILS provides what

A

Vertical guidance down glide path + Horizontal guidance along centreline (localiser)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Localiser

A

Provides guidance left and right to runway
VHF transmitter with 40 dedicated frequencies between 108/111.95MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Glide Path

A

Up and down guidance on approach
Transmits in the UHF/paired with VHF localiser frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

ILS Frequency Band

A

VHF - 108MHz to 112MHz
Odd numbers less than 112 in the VHF band

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Components of ILS

A

Localiser
Glide slope
DME range to indicate distance
Market beacons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ILS is identified by

A

3 letter Morse code

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Principles of localiser

A

Difference of depth of modulation
Blue lobe - 150Hz
Yellow lobe - 90Hz

Modulation increases across lobe to max furthest from centreline
Ac receiver detects and measures depth of modulation in each lobe and calculates the difference.

More 90Hz than 150Hz = left of centreline
More 150Hz than 90Hz = right of the centreline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Errors associated with false localiser beams

A

Reversed sense side lobes cause incorrect indication of the detected modulated frequency (fly right command when already right of centre line)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Localiser coverage range

A

Protected ranges +- 10 degrees of runway centreline out to 25nm
+- 35 degrees out to 17nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Localiser back course

A

Non precision approach on the opposite side on runway - azimuth guidance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Glide path - principles of operation

A

Vertical guidance by overlapping beams of UHF carrier waves

Lower (blue) - 150Hz
Upper (yellow) - 90Hz

More 150Hz signal than 90Hz = below the GP (fly up command)
More 90Hz signal than 150Hz = above the GP (flow down command)
Equal amount of each signal = DDM zero on glide path

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Glide path Coverage

A

+- 8 degrees either side of runway centreline - 10nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

False glide path

A

Lower lobe is blocked by the ground/occurs above true glide path 2x
Standard 3 degree glide path = first false glide path occurs at 3 x 2 = 6 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Outer Marker

A

Indicated the final approach fix
4-7nm from runway threshold
Lowest frequency of the three (400hz)
Blue flashing lights

2 dashes per second - - - - - - - -

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Beam Bends

A

Slight curves which are caused by reflections of the radio wave due to obstructions. Can be followed by the navigation system of aircraft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Middle Marker

A

1nm from threshold
Amber
Medium frequency (1300Hz)
Dots and dashes - 3 dashes per second - . - . - . - . - . -

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

FM broadcast just below 108MHz can cause

A

Interference with localiser signal which may lead to deviation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

ILS beam bends are

A

Slight curves caused by reflection of radio waves due to permanent obstructions. Can be followed by nav systems.

Checked by flight tests

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

ILS warning flag indicates one of the following

A

Absence of carrier frequency
Absence of modulation
% of modulation reduced to zero

20
Q

Different type of precision approaches in ILS

A

CAT I - Not below 200ft (DH) - RVR 550m
CAT II - DH 100ft - RVR 300M
CAT IIIA - DH below 100ft - RVR 200m
CATIIIB - DH below 100ft or no DH - 75m
CATIIIC - No limits - guides along runway

21
Q

Scalloping and ILS

A

Causes rapid indicator changes from side to side of the intended approach path which cannot be followed by the aircraft

22
Q

To be fully established on the localiser before descending on the glide slop the ac must be within

A

1 dot half scale deflection on either side of the localiser centreline.

23
Q

Paired VOR and ILS on approach with half scale deflection of VOR =

A

Full scale ILS (2.5 max deviation)

24
Q

FM immunity filters

A

Used to protect against interference from VHF broadcast transmissions on the localiser and VORs

Not ILS glide slope as this is UHF

25
Q

Warning flag on ILS will trigger when

A

No carrier frequency
No modulation
% modulation reduced to zero

26
Q

Localiser coverage

A

25Nm within 10 degrees of approach bearing

17N, within 35 degrees of approach bearing

27
Q

ILS back course on OBI and CDI

A

OBI will always display reverse sensing

HSI can be turned to face the front course to reverse the indication to give correct sensing of localiser

28
Q

Full scale deflection of a localiser is

A

2.5 degrees (Each dot is 0.5 degrees)

29
Q

Identification of ILS is by

A

3 letter Morse code
Transmitted every 10 seconds on audible channel of the ILS
Via the audio control panel in NAV

30
Q

ILS/DME - co located meaning

A

DME will read 0nm at the threshold
Automatically tuned when localiser frequency is used

31
Q

How does ILS produce guidance

A

A radiation pattern which is amplitude modulated by a 90Hz and 150Hz signal

32
Q

Full deflection on a glide slope indicator indicates the aircraft is

A

0.7 degrees above or below the correct glide path

33
Q

ILS lobes - frequencies

A

The same carrier frequency - VHF - 75MHz
Both Amplitude modulated
Different amplitude modulation

34
Q

Outer Marker is modulated at

A

400hz
- - - - - - -
Rate of 2 per second

4-7nm for threshold

35
Q

Middle Marker is modulated at

A

1300hz
.-.-.-.
2 dashes and 6 dots per second

0.4nm

36
Q

Inner Marker is modulated at

A

3000 hertz (highest frequency)
6 dots per second
. . . . . . . .

37
Q

Audio frequency of markers

A

Inner - 3000hz
Middle - 1300hz
Outer - 400hz

38
Q

ILS facility performance categories (ILS equipment capability\0

A

Not the same as the normal operation figures. Lowest minimums capability of the facility.

CAT I - 100ft or less
CAT II - 50ft or less
CAT III - Down to the runway

39
Q

Glide path Coverage formula

A

(Glide slope in degrees) x 0.45 (lower)
(Glide slope in degrees) x 1.75 (upper)

3 x 0.45 = 1.35 degrees above the horizontal
3 x 1.75 = 5.25 degrees above the horizontal

40
Q

Tuned to a ILS - rotating the OBS will

A

Only rotate the compass card and not have any effect on the deviation display

41
Q

Warning flag appears for ILS when

A

Absence of the modulation
Percentage modulation signal reduced to 0
Absence of the carrier frequency

42
Q

Working out height along glideslope

A

3 degree glide slope = 300ft per mile
4 degree glide slope = 400ft per mile

+100ft per1 degree

43
Q

ILS components - Distances of localiser/glide path/middle market/outer marker

A

Localiser - 300 meters behind end of runway
Glide path - 300 meter behind threshold
Middle marker - 1000 meter from threshold
Outer marker - 4nm from threshold

44
Q

Type A vs Type B

A

Type A - Above 250 DH
Type B - Below 250 DH

45
Q

What is the reversal procedure

A

Starts at fix
Straight leg with track guidance/timed
80 degree turn
260 turn in opposite direction to intercept inbound track

46
Q

Multi path Errors are to be expected in the

A

ILS coverage area

Reflect the ILS signals

Radio Navigation (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions