ILS

Question 1

What information does the ILS provide?

Answer 1

1. Guidance: Localizer, Glide Slope
2. Range (Distance): OM/MM/IM, DME, GPS fix during approaches
3. Visual Information: Approach lights (not a part of the ILS), touchdown centerline lights, runway lights etc.

Question 2

What means can be a substitute for the OM?

Answer 2

• Compass locator
• PAR
• ASR
• VOR
• NDB
• RNAV GPS capable of identifying fixes on a SIAP

Question 3

What is a full scale deflection at the runway threshold for an ILS?

Answer 3

-700’

Question 4

How far out does the localizer provide guidance (i.e. SSV LOC)?

Answer 4

• 18 NM out @ 10° / 1,000’ above highest terrain along course line / 10° along either side of the course
• 10 NM radius 10° to 35° / 4,500’ above the elevation of the antenna site /

Question 5

What is a localizer with an ESV?

Answer 5

• It’s a LOC that can extend beyond the SSV of 18NM of a standard localizer distance
• It can be extended beyond the standard 18 NM with the approval of FAA inspections

Question 6

What is an LDA?

Answer 6

• Localizer Directional Aid
• Not a part of a complete ILS.
• LDA is NOT aligned with the runway
• Can have GS; indicated as “LDA/Glideslope” aka APV

Question 7

What is an APV?

Answer 7

• An approach with vertical guidance
• Based on Nav. system that is not required to meet ICAO Annex 10
• Provides course & glidepath deviation information

Question 8

Can you use a glideslope when shooting the back course of an ILS?

Answer 8

• Not unless specified on the approach and landing chart
• You may receive GS flag to disappear and present an unreliable GS info

Question 9

How wide is the GS beam?

Answer 9

• 1.4° vertically

Question 10

How far can you follow the GS when shooting the ILS?

Answer 10

• The signal provides descent info. for navigation down to the lowest authorized DH specified in the approved ILS IAP
• Any reference below the lowest DH must be supplemented by visual reference to the runway
• GS with no published DH are usable to runway threshold

Question 11

How far down can you utilize the GS if there’s no published DA?

Answer 11

All the way down to runway threshold

Question 12

The GS projection angle is normally adjusted to 3° horizontal in order to:

Answer 12

• Intersect with the MM at about 200’ and the outer marker at 1,400’ above the runway elevation

Question 13

How far out can the GS signal be reached?

Answer 13

• 10NM
• There are ESV for GS that exceed 10 NM

Question 14

What is the size of a marker beacon when directly above the antena?

Answer 14

• 1,000’ above the antenna
• 2,400’ wide
• 4,200’ long

Question 15

What does the MM and OM help identify during the approach?

Answer 15

• OM identifies the FAF
• MM identifies the a position of 3,500’ from the landing threshold (if following the GS you should be 200’ above the elevation of TDZE)
• No MM are required to be installed with ILS

Question 16

What color is the OM on the annunciators?

Answer 16

• Blue
• Identified with “dash dash dash”

Question 17

What color is the MM on the annunciators?

Answer 17

• Amber
• Identified with “dot dash dot dash”

Question 18

What color is the IM when installed on the ILS?

Answer 18

• White
• Identified with “dot dot dot dot”

Question 19

What frequencies are ILS on?

Answer 19

• 108.1 through 111.75
• Every odd tenth, and 5th one (108.1/108.15/108.3/108.35 etc

Question 20

When the ILS GS fails, what minimums can you use?

Answer 20

• Use the minimums published for localizer only approach
• If ever in doubt go missed

Question 21

What is the minimum for an ILS Cat I required visuals?

Answer 21

• DH 200’ and RVR of 2,400’
• w/ TDZE and Centerline lights RVR 1,800’
• w/ Autopilot or FD, HUD: RVR 1,800’

Question 22

What are Cat II ILS minimums?

Answer 22

• DH 100’, and RVR 1,200’ w/ autoland or HUD to touchdown and noted on authorization

Question 23

What are Cat IIIa ILS minimums?

Answer 23

• No DH or DH below 100’ and RVR no less than 700’

Question 24

What are Cat IIIb ILS minimums?

Answer 24

• No DH or DH below 50’ and RVR less than that 750 but no less than 150

Question 25

What are Cat IIIc minimums?

Answer 25

- No DH and no RVR limitation

Question 26

With your IFR license, what Cat approaches are you able to shoot?

Answer 26

- Only Cat I approaches - Additional training required for shooting Cat II and Cat III approaches

Question 27

When may ATC allow an a/c to enter the ILS critical area?

Answer 27

When the landing a/c has: - Runway in sight - Circling to land - Sides-stepping to land on another runway

Question 28

When is no ILS critical area protected for landing traffic?

Answer 28

- When weather conditions are at or above ceiling 800' and/or - Flight visibility is less than 2 miles - Under these conditions, flight crew would advise tower that it will conduct an AUTOLAND or COUPLED approach

Question 29

What is SDF?

Answer 29

- Simplified Directional Facility - Similar to ILS but not aligned with the runway - No GS information - Course may be wider, so less precision

Question 30

The angle of the transmission signal of the LOC frequency is dependent on what?

Answer 30

- It varies with the length of the runway - This is to keep the standard width of the approach course at 700' at the runway threshold