ILS Flashcards
What information does the ILS provide?
- Guidance: Localizer, Glide Slope
- Range (Distance): OM/MM/IM, DME, GPS fix during approaches
- Visual Information: Approach lights (not a part of the ILS), touchdown centerline lights, runway lights etc.
What means can be a substitute for the OM?
- Compass locator
- PAR
- ASR
- VOR
- NDB
- RNAV GPS capable of identifying fixes on a SIAP
What is a full scale deflection at the runway threshold for an ILS?
-700’
How far out does the localizer provide guidance (i.e. SSV LOC)?
- 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 /
What is a localizer with an ESV?
- 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
What is an LDA?
- 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
What is an APV?
- An approach with vertical guidance
- Based on Nav. system that is not required to meet ICAO Annex 10
- Provides course & glidepath deviation information
Can you use a glideslope when shooting the back course of an ILS?
- Not unless specified on the approach and landing chart
- You may receive GS flag to disappear and present an unreliable GS info
How wide is the GS beam?
- 1.4° vertically
How far can you follow the GS when shooting the ILS?
- 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
How far down can you utilize the GS if there’s no published DA?
All the way down to runway threshold
The GS projection angle is normally adjusted to 3° horizontal in order to:
- Intersect with the MM at about 200’ and the outer marker at 1,400’ above the runway elevation
How far out can the GS signal be reached?
- 10NM
- There are ESV for GS that exceed 10 NM
What is the size of a marker beacon when directly above the antena?
- 1,000’ above the antenna
- 2,400’ wide
- 4,200’ long
What does the MM and OM help identify during the approach?
- 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
What color is the OM on the annunciators?
- Blue
- Identified with “dash dash dash”
What color is the MM on the annunciators?
- Amber
- Identified with “dot dash dot dash”
What color is the IM when installed on the ILS?
- White
- Identified with “dot dot dot dot”
What frequencies are ILS on?
- 108.1 through 111.75
- Every odd tenth, and 5th one (108.1/108.15/108.3/108.35 etc
When the ILS GS fails, what minimums can you use?
- Use the minimums published for localizer only approach
- If ever in doubt go missed
What is the minimum for an ILS Cat I required visuals?
- DH 200’ and RVR of 2,400’
- w/ TDZE and Centerline lights RVR 1,800’
- w/ Autopilot or FD, HUD: RVR 1,800’
What are Cat II ILS minimums?
- DH 100’, and RVR 1,200’ w/ autoland or HUD to touchdown and noted on authorization
What are Cat IIIa ILS minimums?
- No DH or DH below 100’ and RVR no less than 700’
What are Cat IIIb ILS minimums?
- No DH or DH below 50’ and RVR less than that 750 but no less than 150
What are Cat IIIc minimums?
- No DH and no RVR limitation
With your IFR license, what Cat approaches are you able to shoot?
- Only Cat I approaches
- Additional training required for shooting Cat II and Cat III approaches
When may ATC allow an a/c to enter the ILS critical area?
When the landing a/c has:
- Runway in sight
- Circling to land
- Sides-stepping to land on another runway
When is no ILS critical area protected for landing traffic?
- 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
What is SDF?
- Simplified Directional Facility
- Similar to ILS but not aligned with the runway
- No GS information
- Course may be wider, so less precision
The angle of the transmission signal of the LOC frequency is dependent on what?
- 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
