Struggling with glideslope bar

[Aeger]

Experiencing problems trying to land at Lochini-Tbilisi using ILS...

 

I've confirmed that I have the right ILS frequency (108.90 for runway 31), that my ILS is powered and set on my NMSP, however I cannot get my localizer bar to point me in the direction of the runway, it always seems to be pointing off to the side (which guides me off the path of the runway). The glideslope seems absolutely fine though...

 

Any ideas? Thanks!

 

Attached screenshot as example.

Edited August 8, 2015 by Aeger

[Wolf Rider]

bank left a bit and throttle back some

 

the yellow needles act as Flight Director (indicating to you as to which way to go) and not as an ILS repeater (letting you know where you are)

[chaos]

bank left a bit and throttle back some

)

 

From where I'm sitting, he's smack-dab in the chute. No reason for the roll-bar to be so far off the side. To me it looks like a bug in the FD system. I know that, in the past, there were some issues with the front-course being off at some airports (I.e. not coinciding with the runway heading).

 

To OP; the Glideslope is fine. The Localizer is off to the side ;)

Edited August 7, 2015 by chaos

[DirtyFret]

I bet that the issue is because Tbilisi-Lochini (UGTB) has no runway 31 but a runway 30L with a heading 301. I assume you've set the heading knob to 310 and that might be the confusing factor. I would politely suggest that you try setting it to 301.

Edited August 7, 2015 by DirtyFret

[Flamin_Squirrel]

I bet that the issue is because Tbilisi-Lochini (UGTB) has no runway 31 but a runway 30L with a heading 301. I assume you've set the heading knob to 310 and that might be the confusing factor. I would politely suggest that you try setting it to 301.

 

That's not it. ILS data isn't like VOR/TACAN; the couse selector has no affect on it.

 

This assumes no DCS bugs of course.

[howie87]

That's not it. ILS data isn't like VOR/TACAN; the couse selector has no affect on it.

 

This assumes no DCS bugs of course.

 

Erm, yes it does. The flight director uses information from the the glideslope and localizer singals but it also needs to know the intended course to generate correct steering commands. Try playing around with the course dial on final approach. You'll find it does indeed have an affect.

[St3v3f]

That's not it. ILS data isn't like VOR/TACAN; the couse selector has no affect on it.

 

This assumes no DCS bugs of course.

 

The course selector has no effect on ILS but it does on the FD

 

http://forums.eagle.ru/showthread.php?t=70045

[howie87]

Baron, you old dog! How the devil are you?

 

I dug up this old thread with lots of input from Olgerd who actually wrote the code for the ILS in DCS.

 

http://forums.eagle.ru/showthread.php?t=115053&page=6

[Joni]

Nope. Nor the FD or ILS CDI use course settings (basic IFR). The FD is bugged in DCS but not all the times, it has strange behaviour depending on the situation.

 

In DCS, FD and ILS CDI seem to be working according to the course set, which should not happen as it is not how all instrument are built in this planet at least.

 

All runways headings are affected by magnetic deviation, so if the runway is 31 then the heading you should set according to the Georgia current deviation (and assuming DCS models it) will be around 305 or 301 instead of 310.

 

 

I am a naval aviator and have never seen this working properly in DCS. In fact, all navigation simulation is poor within DCS, but the systems and combat are magnific.

 

 

Hope this clarifies.

 

 

Thanks.

[Flamin_Squirrel]

Erm, yes it does. The flight director uses information from the the glideslope and localizer singals but it also needs to know the intended course to generate correct steering commands. Try playing around with the course dial on final approach. You'll find it does indeed have an affect.

 

Raw ILS data is definitely not influenced by course setting, but I'm prepared to be proven wrong on the FD (I've not heard of it before, but it's perfectly possible that's an A10 feature). Do you have references?

 

I would say though, just because it has an affect in DCS doesn't mean it's correct.

[DirtyFret]

Nope. Nor the FD or ILS CDI use course settings (basic IFR). The FD is bugged in DCS but not all the times, it has strange behaviour depending on the situation.

 

In DCS, FD and ILS CDI seem to be working according to the course set, which should not happen as it is not how all instrument are built in this planet at least.

 

All runways headings are affected by magnetic deviation, so if the runway is 31 then the heading you should set according to the Georgia current deviation (and assuming DCS models it) will be around 305 or 301 instead of 310.

 

I am a naval aviator and have never seen this working properly in DCS. In fact, all navigation simulation is poor within DCS, but the systems and combat are magnific.

 

Hope this clarifies.

Thanks.

 

 

Raw ILS data is definitely not influenced by course setting, but I'm prepared to be proven wrong on the FD (I've not heard of it before, but it's perfectly possible that's an A10 feature). Do you have references?

 

I would say though, just because it has an affect in DCS doesn't mean it's correct.

 

A source: A10-A manual.

 

p.s. source courtesy of Vibora from that "old" thread

Edited August 7, 2015 by DirtyFret

[Joni]

A source: A10-A manual.

 

You realize that you just proved I was right? :P

 

 

What the manual means is that the FD takes data and signals from the HSI in terms of current heading and the course that THE FREQUENCY SET IN THE ILS RADIO HAS LOADED FROM THE GROUND.

 

So the course you select with the knob will not affect the HSI needles or FD yellow drivers, period.

 

 

The manual is very clear, but if it's not enough you can always refer to how systems are built and the redundancy that this would give.

 

 

Thanks.

[DirtyFret]

You realize that you just proved I was right? :P

 

 

What the manual means is that the FD takes data and signals from the HSI in terms of current heading and the course that THE FREQUENCY SET IN THE ILS RADIO HAS LOADED FROM THE GROUND.

 

So the course you select with the knob will not affect the HSI needles or FD yellow drivers, period.

 

 

The manual is very clear, but if it's not enough you can always refer to how systems are built and the redundancy that this would give.

 

 

Thanks.

 

My apologies, my previous reply might have come across as antagonistic. Not my intention.

 

My intention was to help solve OP's issue and given the information on that A10-A manual page, the info he/she gave us and the explanation from Olgred (the ED ILS coder guy) I believe that it would be worthwhile for the OP to test if the course setting being wrong might be the issue for him in DCS.

[Joni]

I just read Oleg's posts, and now I can see why this is happening. Not even the developers team understand how this works in real life, so they coded it wrong in the first place, confusing all of us into how it works in DCS and how it should work.

 

So I guess that if ED thinks that the course knob affects FD or HSI during ILS then there is no hope at all to get this fixed.

 

 

DCS is the first sim I see this not working properly. Even FSX (with all the limitations) replicates navigation correctly. But I guess that since FSX is merely for navigation training then it's normal that it works, when DCS is a much more complex simulator and it has room for mistakes.

 

 

Dont get me wrong, I love DCS so much.

[Joni]

Im a pilot too and I can say that all Johnny said is true in real life. Despite his reputation he is correct so far.

 

 

There could be some veeeeery old systems that use course knob indication to feed the FD but those systems didnt last long.

[Flamin_Squirrel]

My apologies, my previous reply might have come across as antagonistic. Not my intention.

 

My intention was to help solve OP's issue and given the information on that A10-A manual page, the info he/she gave us and the explanation from Olgred (the ED ILS coder guy) I believe that it would be worthwhile for the OP to test if the course setting being wrong might be the issue for him in DCS.

 

Don't worry, it didn't. In all honesty I probably shouldn't have brought it up, as regardless of whether it's modelled correctly, it may have solved the OP's problem. My bad. At least we've learnt something :smartass:

[DirtyFret]

[...]

Dont get me wrong, I love DCS so much.

 

me too:thumbup:

 

This can be very confusing for non-english speaking non aviation pro's like me.

 

That manual page for example says "...FDC also obtains heading and course error signals from the HSI..." further below it states "ILS localizer deviation signals are supplied to the CDI on the HSI...".

 

This is where it gets superconfusing for me - isn't the CDI displaying course deviation(=course error?) in relation to the course set and the desired course set is set by the course knob as stated by the DCS A10-C manual?

 

But then again I do believe I am are straying a bit off-topic so I'll just keep my fingers crossed OP has been able to solve this.:pilotfly:

Edited August 7, 2015 by DirtyFret

[Joni]

Hi again guys, I wasnt trying to be rude ro anything either. So we are all cool.

 

 

I think I can explain this in a clearer way.

 

 

When you select ILS as the HSI source, then it wont matter what course you set, the ILS will always give you relative position to the localizer and the glideslope in the HSI.

 

Therefore, the FD takes all signals from the HSI and tells you where to point the aircraft to intercept those electronic lines calls localizer and glideslope. Once you get close to them the FD will tell you to go left or right/up or down to keep on track once intercepted.

 

So one way to understand this is to think that if the HSI does not rely on course selector, then why would the FD care about how it is set. The FD just watches that if the HSI needle is to the right (for example) then you must turn right to a certaing interpection heading. The FD needle will then go to the center since you are already in the interpection heading and once you finally intercept the localizer the FD will tell you to go left to maintain the localizer heading. :)

[Joni]

I just remembered that the course knob can be used for Back Course Approaches, which are rare.

[Joni]

I tested this and the FD is directly influenced by the course selector :S

 

One of the first basic IFR lessons we get is that FDs are built not to take data from the course selector knob but from the ILS signal (which is just one instead of 360 from a TACAN or VOR) to mitigate any pilot or magnetic drift error input in the selector.

 

Makes me really sad to see such a basic IFR system not working as it should :(

 

At least the bearings on the kneeboard are correct and we can actually set them to make the FD work correctly.

 

 

Cheers guys!

[Aeger]

Wow, thanks guys for the feedback and wealth of information. Much appreciated. Good community here.

 

Johnny your comment below was spot on. As soon as I set my heading to 301, the localizer bar snapped right into place and aligned with the runway.

 

Nope. Nor the FD or ILS CDI use course settings (basic IFR). The FD is bugged in DCS but not all the times, it has strange behaviour depending on the situation.

 

In DCS, FD and ILS CDI seem to be working according to the course set, which should not happen as it is not how all instrument are built in this planet at least.

 

All runways headings are affected by magnetic deviation, so if the runway is 31 then the heading you should set according to the Georgia current deviation (and assuming DCS models it) will be around 305 or 301 instead of 310.

 

 

I am a naval aviator and have never seen this working properly in DCS. In fact, all navigation simulation is poor within DCS, but the systems and combat are magnific.

 

 

I'm glad this is resolved, but at the same time somewhat sad that it isn't properly modeled :cry:

 

Hopefully this will get addressed at some point.

 

Cheers all.

[Joni]

Glad to help :)

 

I really hope this is fixed someday, DCS is too good to have something so basic not modeled correctly.

 

Be sure to check the VAD charts on the kneeboard (shift+K) to know the exact course for each airport and that way you should be good with the FD.

 

 

Cheers.

[sydost]

Hello Gents,

 

just as a reminder that there actually is plenty of equipment out there with a different operating logic than the industry norm I can tell you that in my daily driver the flight director is very much influenced by the selected course during the capture phase of an ILS approach. Though, no influence on the tracking phase.

 

That in mind I would not be so quick to judge that the flight director modelling in DCS A-10C is absolutely wrong. Probably something that should be looked into or confirmed but it might even be possible that it could work like the real deal.

[Wolf Rider]

hey... if you're off the localiser, you're off the localiser and glide scope, for that matter.

The compass might be 20 / 30/ 90deg (pick one) off track alignment... but the TACAN will be out, not the localiser - unless the Localiser is out as well

Edited August 8, 2015 by Wolf Rider

[Joni]

Hello Gents,

 

just as a reminder that there actually is plenty of equipment out there with a different operating logic than the industry norm I can tell you that in my daily driver the flight director is very much influenced by the selected course during the capture phase of an ILS approach. Though, no influence on the tracking phase.

 

That in mind I would not be so quick to judge that the flight director modelling in DCS A-10C is absolutely wrong. Probably something that should be looked into or confirmed but it might even be possible that it could work like the real deal.

 

It is true that we might be wrong, but I've never flown an aircraft in my entire life that has an FD doing that, 1st because is against regulations (Johnny explained why), and second because the an ILS has only one signal in only one direction therefore both the HSI and FD have only one signal to track so it is impossible to make the FD change by the influence of course selector even if the builders wanted to (Johnny explained this as well).

 

 

You need to understand how all systems work and then you'll see that even if they wanted the FD to track more than one signal it'll be impossible since there is only one in an ILS transmitter.