Questions tagged [ils]

An instrument landing system (ILS) is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway.

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Why is a higher DDM value used for the ILS GP than the localizer?

The difference in the depth of modulation (DDM) value for the glidepath (GP) is 17.5% and for the localizer is 15.5%? Why is the value higher for the GP?
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After tuning and identify an ILS, do you mute the audio? How/where do you hear marker beacons?

I've practiced tracking an VOR radial in VFR conditions with a CFI. We tuned and identified the VOR, muted the Morse code, set the OBS, and then followed the CDI needle indications. I have not used a ...
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10 votes
1 answer
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How much obstacle clearance is provided within full scale deflection below glide slope on ILS?

Basically the question in the title. The military has regulations that say to obey the localizer minimums if more than have scale deflection below glide slope, but for civilians how much obstacle ...
3 votes
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Why is there no final approach fix symbol on some of the Jeppesen VOR charts? (Maltese Cross Symbol)

Why is there no final approach fix symbol on some of the Jeppesen VOR charts? (Maltese Cross Symbol) What does the box marked with a red arrow mean when there is no FAF symbol and how is it defined? ...
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Why if you tune localizer frequency the glide slope is tuned too?

if tuning the ILS you tune localizer freq which is between 108 MHz to 111.975 MHz. why the glide slope freq which operates in the 328.6–335.4 MHz band is tuned simultaneously?
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Which one is racetrack? Isn't it a holding over VOR on the left and holding over FIX on the right?

Which one is a racetrack? Isn't it a holding over VOR on the left and holding over FIX on the right? If one of them is a racetrack, how is it different from holding? Or are they both used in the same ...
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2 votes
1 answer
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What are the meanings of the numbers "4500" written under the VOR and NDB boxes? (MHA?) (Recommended crossing altitude?)

Does it directly mean the minimum altitude for holdings on VOR or NDB or can it be interpreted in another way? Because MHA 4500 information for the holding is given on the right side. This picture is ...
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What is this black star symbol in the picture below? If it means a hazard with no altitude information, what kind of hazard is that?

What is this black star symbol in the picture below? If it means a hazard without altitude, what kind of hazard is that? A separate picture of similar symbol with altitude information:
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What is MEHT (minimum eye height over the threshold)?

What is MEHT (minimum eye height over the threshold)? I can't find the definition and how to use it.
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1 answer
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What are the meanings of the codes depicts in the square brackets? For example: [MDØ68]

I always see these codes inside of the square brackets with different charts. Especially I wonder about the meaning of Ø.
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Why is there no Maltese Cross in this non-precision approach's profile view which has a FAF?

I am wondering why this chart does not show the FAF with a maltese cross as it is used in non-precision approaches to depict FAF.
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How does an aircraft work with ILS [closed]

In what situation will an aircraft show you "LOC*" in FMA? What signal does the aircraft received when LOC*?(how does the aircraft know it is on LOC*) And which heading will the aircraft ...
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Crossing extended runway centerline while intercepting LOC

I know it shouldn't happen but in case it happens for whatever reason, what is correct procedure to save the day. I mean the case that the aircraft is turning but it gets to the wrong side by, let's ...
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Why are visual and ILS approach angles different for a Cessna 172?

NOTE: I fly in CANADA. Also, the question is specific to light aircraft like a C172. It is known that the (standard) glideslope flown in an ILS approach is 3o to the T point[1]. However, that is not ...
5 votes
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What is the speed of the approach lights rabbit?

If you were flying past the rabbit and passed each bulb as it lit, what speed would you be flying at? The rabbit is 2400 feet long, spaced at 100 foot increments and consists of 15 lights. The math ...
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10 votes
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ILS Approach, when can you descend on the glide path?

The following quote is from G. Bristol’s book, Ace the Technical Piloting Interview: You can descend on the glide path when You have been cleared for the ILS procedure. You have captured the ...
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If the glideslope signal is higher than it should be, can I continue the approach? [duplicate]

When I'm passing Precision Final Approach Fix, if my glideslope is two dot above, and my altitude is at PFAF altitude, can I continue my approach with this glideslope signal? Is it legal? I think the ...
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What would a Category II ILS approach require that a Category III approach wouldn't?

According to @RalphJ's first comment on my earlier question about ILS approaches in an E-Jet sans pitch trim: Are you sure that Cat III approaches are allowed in that condition? Typically, Cat III ...
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2 votes
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What are the operational differences between the ILS CATs? [duplicate]

I know ILS CAT is classified by DH, and RVR, but I want to know what's difference between ILS CAT operationally. For example, CAT 3 approach should be autolanding. (I am not sure) And, if RVR is 600m ...
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3 votes
1 answer
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Can a Localizer Backcourse signal be reversed (at the site antenna)?

Can the two Localizer Backcourse signals (90Hz and 150 Hz) be reversed (at the site antenna) eliminating reverse needle sensing when flying a Localizer Backcourse approach? If so, are there any ...
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4 votes
3 answers
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Interpreting Missed Approach Section in Jeppesen Chart

While interpreting an RKPS(airport located in South Korea) LOC DME 06L, I found it somewhat confusing. As you see, the initial action of the missed approach is climbing via heading 063 to GIDOO. I ...
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What should I do if I intercept the glideslope before reaching the final approach fix?

On several of the ILS and RNAV LPV approaches in my area (and notably the ones I expect for my checkride), I consistently intercept the GS at 0.1-0.2nm before the FAF. An example: I am flying at ...
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3 answers
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If cleared for an ILS approach at the Initial Approach Fix, where should I intercept the glideslope?

I am a brand new Instrument Pilot and the answer that I am looking for is related to good technique and not necessarily not what is legal or not. My instructor taught me that when flying an approach ...
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Why is the LOC RWY 26 approach at Innsbruck classified as LOC instead of ILS or IGS?

After reading about Localiser Type Directional Aid (LDA) and Instrument Guidance System (IGS) on SKYbrary, my understanding of classifying these approaches is this: Course Offset With GP Without GP ...
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Is it necessary to switch from VFR to IFR when using ILS approach?

I have flown at an airport and asked for vectors for an ILS approach in VMC for practice. But the controller refused to give me vectors and told me that I could only have a visual approach. I got the ...
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Is there any latest List of CAT IIIB airports in the world?

Recently I had my very first CATIIIB experience at my own homebase (VILK) and since then I've been keen to know more about this most advanced landing system we have in the aviation as of now and given ...
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What ILS type approach my flights landing could be?

I had one of the foggiest landing experiences recently and I'm interested if any of you could guess what type of ILS could it be like CAT I,II,IIIA or IIIB? So the METAR issued 9 minutes before my ...
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Can autopilot track ILS without any internal heading reference?

I am asking about the internal design of the autopilot of a CRJ200 (no autoland). I was flying an ILS approach when the AHRS heading started to drift rapidly by 30 degrees. The autopilot somehow was ...
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Why would an ILS have a glide path angle less than the preferred 3°?

According to EASA the preferred Glide Path Angle is 3°: EASA Easy Access Rules - Page 22 - 4.1.2.1. There are some airports (e.g. Larnaca 2.75°) which are using a lower Glide Path Angle than 3°. Using ...
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Are both RVR and visibility minimum required for CAT I ILS?

Is it required to have both RVR and visibility to be more than minimum for ILS CAT 1 or one of them is acceptable. If both required which one has priority.
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What is ILS CLASS in this airport NOTAM?

I have seen this NOTAM for UAII /CIT SHYMKENT airport and they mention ILS CLASS for runway 10/28, Does anyone knows what it means? NOTAM: NOTAM K3998/20: Shymkent Airport (UAII) K3998/20 NOTAMN Q) ...
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How do I know which airports have ILS and for which runways?

I have been into flying for years but something I can't figure out is how do I, as a pilot, know if an airport I am going to has ILS, which runways would have it and why do only some have it but the ...
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Why is the ILS16 approach at KSKF not available in my Garmin 430W?

I am doing flight instruction on the San Antonio area (Texas) and I've been shooting different approches on the vecinity airports. One of the approaches I usually execute is the ILS 16 at KSKF, which ...
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Why are different distances listed for the ILS and the LOC on this approach chart?

Maybe someone has an idea why are there two separate distance values (marked in blue) for ILS and LOC approaches?
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Why is the ILS 36R approach at ZBAA over twice as long as a standard ILS approach?

I fly exclusively in a consumer flight simulator, so excuse me if there's an obvious answer to this. ILS approach plates typically show a long, arrow-like symbol to indicate the part of an approach ...
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How to choose the right ILS when the runway has more than one?

I'm wondering how is the right choose when an runway has ILS x, Y, Z. What should I consider in order to pick one of those for landing?
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Does a portable ILS ground station exist?

Does anyone know of a good example of a portable ILS ground station? I mean, it can be used for temporary airfields.
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How big does an object in one of the ILS critical areas have to be to cause a problem?

ILS installations have a critical area extending some distance back from the glideslope antenna (primarily due to most glideslope transmitters’ needing to bounce one of their two beams off the ground ...
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How do I follow an ILS glideslope on the ADI in Falcon BMS?

I'm currently flying the ILS landing mission in Falcon BMS, I'm practicing landing using the instruments (head down) and although I'm mostly OK with the LOC, I struggle to maintain a 2.5 degree ...
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Why do the GS and LOC indicators blink?

So, the question is in the title. Specifically referring to this video. At around timestamp 2:10 in the video, you can see the GS and LOC indicators blink. Why does it blink?
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Are ILS CAT IIIA minimums based on the radar altimeter or on barometric altitude? [duplicate]

From what I understand the CAT II ILS minimums on the far right are based on radar altimeter 102'AGL and barometric altitude DA(H) 429'MSL (100'ATL). But what about the CAT IIIA minimums in the ...
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How many African countries currently deploy Cat 3 ILS? [duplicate]

How many countries in Africa currently operate Cat 3 ILS?
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1 answer
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Why are Category II ILS approaches prohibited in an E-Jet with inoperative pitch trim?

Part of the Pitch Trim Runaway checklist for the E-Jet family states that Category II ILS approaches are prohibited if neither pitch trim channel is available: If both pitch trim channels are failed: ...
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How often is ILS accuracy checked?

I imagine checking ILS accuracy by measuring ILS signals at various points along the approach path is routine maintenance, although I don't know how it is done. How often must this kind of check be ...
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With current technology, why is there still increased separation between aircraft and delays in low visibility conditions?

Since most (if not all) commercial aircraft are equipped with inertial and satellite/GPS navigation, why is increased separation between aircraft necessary? Can't controllers immediately identify the ...
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If you were to fly an ILS in a knife edge would you receve GS and LOC be flipped?

because LOC and GS work the same way, if you were to fly one at 90 degrees bank would your information be displayed on the wrong indicators?
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Is there a list of airports with Category 3 ILS systems?

Is there a list of airports with category 3 Instrument Landing Systems?
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Can you continue an ILS approach when weather falls below minimum?

If, after passing the final approach fix, weather deteriorates so that the reported values are now below required minima, is it allowed to continue the approach?
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What is the difference in purpose of the 1:40 Obstacle Identification Surface and the 1:50 clearance plane for an ILS glideslope?

I have found references to the Obstacle Identification Surface (OIS), which is approximately a 152ft/NM slope from the end of the runway (1.43 degrees, 1:40 rise/run) and a 1:50 clearance plane noted ...
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362 views

Distance to the runway/ touchdown point

Trying to learn about aviation, and looking through all the displays in the cockpit, and also the Garmin G1000, I am not sure where I see the distance to the runway touchdown point, or the start of ...
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