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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1answer
346 views

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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1answer
75 views

How many African countries currently deploy Cat 3 ILS?

How many countries in Africa currently operate Cat 3 ILS?
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1answer
834 views

How to calculate DDM in a ILS dual frequency system?

I'm working in a project where I have to process ILS baseband signals. I have no problem obtaining DDM value from single frequency signals, nor the individual components of a dual frequency signal (...
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22 views

What is considered to be a approved deviation in an ILS beam during a CAT3 approach?

For category 3 approaches, the airport has to transition to LVP mode. In this mode- the holding points are taken back a little bit and the runway surroundings are clear. My question is- Is there a ...
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1answer
201 views

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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1answer
81 views

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 ...
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2answers
104 views

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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2answers
2k views

What is the correct name for this ILS Indicator?

What is the correct terminology for the name of the aircraft instrument that looks like this?
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4answers
2k views

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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1answer
1k views

Are zero visibility landings a possibility for the future of commercial aviation?

Airports usually close or slow down activities in fog conditions, e.g. this seems to be a significant problem in winter at Delhi airport. Large commercial aircraft would be able to land with no ...
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1answer
199 views

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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2answers
1k views

Can civil pilots *ever* fly military high-altitude penetration approach procedures?

Let's say I'm flying some business types in a Gulfstream III (an approach category C aircraft) from Stockton to Palmdale to meet up with some USAF types there (new airplane deal, wooo!). Can I accept/...
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3answers
3k views

Is it legal to land in bad visibility conditions without ILS?

Korean Air Flight 801 crashed during bad visibility conditions in Guam because the ILS was out of commission and the pilot thought it wasn't. My question though is why he even tried to land there in ...
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87 views

Can you identify this ILS/VOR antenna?

I'm looking for an ILS/VOR cheap and lightweight antenna. I can see there are several models (p.e. aircraftspruce catalog) but the following one drew my attention: All I know is it's being used by a ...
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1answer
6k views

How is varying modulation depth achieved by localizer ground transmitters?

An approaching aircraft's navigation receiver uses the difference in depth of modulation between the 90Hz and 150Hz signals which are amplitude modulated onto an RF carrier (on a channel between ...
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3answers
2k views

Why would the USAF have no support for autolanding?

One thing I noticed when reading through the KC-10 flight manual (see page 184 for the specific reference) is that the KC-10 lacks support for Category III operations, unlike its civil DC-10 brethren. ...
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1answer
313 views

Can a deployable ILS operate in CAT II or CAT III?

Can a deployable ILS operate in CAT II or CAT III? As far as I know a deployable ILS can operate only in CAT I.
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1answer
336 views

How does an eILS improve throughput (for the A380)?

While researching where Heathrow's MLS approachs had gone, the only thing I could find is a topic on Heathrow's new eILS (enhanced ILS). As of the topic's date (Aug 2015) it seems eILS is only ...
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4answers
9k views

Can the ILS glideslope be intercepted from above?

Is it recommended to intercept the ILS glideslope from above? Are there any special considerations like unstable approaches or GPWS warnings?
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1answer
195 views

What are the procedures for flight checking a glideslope and localizer?

What are the FAA and ICAO requirements and procedures for flight checks and calibration of glideslope and localizer transmitters? I'm interested in both the engineering and piloting aspects.
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1answer
325 views

What is the reference plane for the ILS glideslope angle?

Is a 3-degree glideslope based from the runway surface slope at the point where the antenna is installed or is it referenced to a zero-degree plane? If you know of a design document or FAR/AIM ...
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1answer
8k views

What is the behavior of false glideslope signals?

I know that an ILS transmits not only the correct glideslope but also signals that can be interpreted as a false glide path. But I'm not familiar with the details of these erroneous indications. What ...
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1answer
7k views

Precision Approach systems: Why is ILS used more frequently than PAR and MLS?

I have studied that the main three systems for performing Precision Approaches (PA) are the ILS (Instrumental Landing System), PAR (Precision Approach Radar) and MLS (Microwave Landing System). ...
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2answers
664 views

Why haven't helicopter CAT III procedures ever been developed?

Why is there no helicopter equivalent to air transport CAT III ILS? This PPrUNe thread discusses that some helicopter manufacturers have tested coupled approaches down to very low visibility minima (...
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45 views

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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3answers
2k views

Why would a PAPI and ILS glide slope for the same runway not coincide?

Some pilots are reporting the glide slope on our PAPI is not coinciding with the glide slope on our ILS even though FAA did a flight check of our PAPI's. Are there any reasons why a PAPI and ILS would ...
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2answers
133 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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2answers
2k views

How does a pilot select the correct ILS when the airport has parallel runways?

How do you not mess up ILS on parallel runways? There are many airports with ILS and parallel runways, how do you select which ILS for the runway you want? For example there are RWY 22L AND 22R and ...
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46 views

Is ILS secured from being hacked/overriden/disturbed? [duplicate]

Since ILS uses radio frequency. Then is it possible that some one transmit a malicious signal on the same frequency ? Are there any measures to prevent that ?
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1answer
267 views

How is the center ILS used on the 747-400?

The aircraft has 3 ILS receivers, but only ILS L and R in the CDUs. How does the ILS C is put into action?
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2answers
182 views

Reason for the multiple sidelobes in an ILS glideslope signal

Why are there multiple side lobes in the glide slope signal from an ILS?
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1answer
977 views

What is an obstacle identification surface and why would a pilot intentionally penetrate it during an ILS approach?

What is an obstacle identification surface? Why would a pilot intentionally penetrate it during an ILS approach?
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1answer
2k views

What is “(CFMCC)” on an ILS approach chart?

I'm studying the ILS or LOC RWY 3 approach chart for KMKC. I'm trying to figure out what "(CMFCC)" at the runway means. Is it a computer navigation aid?
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3answers
605 views

What prevents the use of a multi-segment ILS for non-straight approaches?

An ILS, consisting of a localiser beam to provide lateral guidance (which can also be used on its own for a non-precision approach) and a glideslope beam to provide vertical guidance, is (currently) ...
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2answers
742 views

Why are there no RNAV (ILS) approaches?

While studying the PBN (FAA Order 8260.58A) and TERPS (FAA order 8260.3D) documents, I still have some trouble figuring part of the logic behind the naming and definitions of the published IAP Charts. ...
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2answers
636 views

How do preceding aircraft affect the ILS signals?

(airliners.net) Planes on approach in sequence to London Heathrow. When LVP is in effect, the ILS area is protected. I'm wondering, when there is a queue to a runway, how does the long queue affect ...
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1answer
191 views

Does the glide slope flag detect percent of modulation (80%)?

Please advise if the glideslope flag validates that the received frequency is being modulated at nominal 80% or 40% for a localizer.
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1answer
47 views

Has mod percent changed for Mark-1 glide slopes?

Mark-1F glide slopes operate at 80 percent modulation. What was it for earlier versions i. e. Mark-1C, Mark-1D, etc.
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1answer
209 views

Can I execute an ILS approach using a NAV CDI with LOC signal only?

I have been flying a small Cessna airplane that has a COM/NAV NARCO MK12 equipment with CDI (lateral needle only). This CDI does not incorporate a horizontal needle to provide vertical guidance, so ...
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1answer
435 views

Can two opposite localizers to a single runway be on simultaneously?

In case of a single runway with two separate ILS systems (one in each end, facing localizers) operating on two different frequencies, can both localizers be on and transmitting at the same time, or ...
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1answer
454 views

Is the callout “minimums” on the 737 used to describe DH on precision approaches

So, I have heard that decision height (DH) is used to signify the height on a precision approach which the pilot has to decide whether to continue or not. But, in the 737, I only hear "approaching ...
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2answers
558 views

What does ''NAV ILS OUT OF SERVICE'' mean?

Just curious about the NOTAM below: !SMF 01/045 (KSMF A0080/19) SMF NAV ILS RWY 16L OUT OF SERVICE 1901180419-1901262359 Does that mean only the glideslope is broken so we can still do a LOC ...
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1answer
2k views

How do you choose CAT II vs. CATIII ILS?

When should we use CAT II or III during landing in bad weather? What we have in our country the standard shows 800m and RVR of 550 m for the ILS, which category procedure should be used if the ...
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1answer
269 views

Do Instrument Landing Systems restrict building heights and can these be overcome?

A recent territorial spat between the countries Malaysia and Singapore over an ILS implementation made me curious. I'm interested in finding out about ILS and how an implementation of one would affect ...
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3answers
355 views

Do any aircraft have a “self-contained ILS”?

The ILS is an invaluable aid to pilots, especially those operating to/from the many airports where poor weather is common (low-visibility operations would be completely impossible without an ILS); ...
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1answer
842 views

Why are the minimums between these two ILS instrument approaches to the same runway so different?

The minimums for the Van Nuys ILS Z Rwy 16R are 1095/40. The minimums for the Van Nuys ILS Y Rwy 16R are 1461-1 1/2. Question: Why are the minimums for the ILS Z so much lower than the minimums for ...
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1answer
936 views

Does ATC prefer ILS over RNAV?

Listening to APP for several major (US class B) airports, it seems that every flight is vectored to intercept the localizer. Is it really possible that 100% of flights filed an ILS approach? If so, ...
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0answers
141 views

Diversions because of fog: What are the reasons?

It's fog season again around my local airport MUC (EDDM), and I have noticed a number of diversions recently. Some planes were holding a bit before attempting to land, performed a go around and then ...
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4answers
331 views

Do different planes (category) aim differently in the 'final stages before flaring'?

(youtube.com) Do different planes (categories A through D) aim differently in the final stages before flaring? I'm asking about precision runways. The reasons I ask: An ILS' glide slope is not ...
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3answers
619 views

Why are the modulation depths of the localiser and glideslope different?

Why do we use a modulation depth of 20% (for 90Hz and 150Hz each) in the case of the localiser and 40% (for 90Hz and 150Hz each) in the case of the glideslope? Why not use 20% for both?