ILS Problem (Resolved)

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memeyer
Posts: 49
Joined: Tue Mar 27, 2018 4:29 pm
Location: Gardner, Kansas

ILS Problem (Resolved)

Post by memeyer »

Has anyone had a problem with the ILS losing HOLD as you near an airport: KDEN: 34R,35R, STAYS LOCKED until touchdown. 7 & 8 as I near the airport the ILS does NOT keep the plane aligned with the runway. I have had the same issue with other airports. Some ILS's hold all the way others DO NOT. HELP! Thanks

Jetcos
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Re: ILS Problem

Post by Jetcos »

This could be a MAGVAR issue in P3D. 8-9 year old data. Add-on scenery can come in to this as well. Updated scenery will change the headings and could change frequencies.

There is a site where you can download the latest MAGVAR.

https://www.aero.sors.fr/navaids.html Follow the instructions.

Then there is a Build Position Database program (Peter Dowson) that is located here:

C:\Sim-Avionics\Navigation_Data

Follow the instructions on the screen when you open the program, once you have installed the latest MAGVAR, Make RWY program and created the latest csv files you run the Build Position Database. This takes all the add-on scenery and complies it. Then things get lined up based on the add-on scenery.

This may help, it may not. But it is something to think about updating at some point or when you add scenery.

Let us know how it goes?
Steve Cos
Vice President and Tech Support
Flightdeck Solutions (FDS)

Rigilkent
Posts: 85
Joined: Wed Aug 02, 2017 11:31 am

Re: ILS Problem

Post by Rigilkent »

I can add some to this as I have been diagnosing this very thoroughly in the last few weeks.

First MakeRwys won't see the sceneries added with the new system that LM implemented for add-ons so make sure you also copy the LorbySceneryExport.exe tool in the same folder from where you launch MakeRwys.exe.

aero.sors magdec.bgl file can sometimes even more up to date than charts (so for example if you use navigraph you can still experience some discrepancy between the published ILS crs and the actual crs that the magdec.bgl would calculate -- which is what the a/p would try to follow).

(Example: I fly to LIRF very often. Published crs for ILS rwy 16R according to the most up to date AIRAC is 161 because the true crs is 163 and the magnetic variation the chart uses is 2degrees East so 161 magnetic.
However the updated magdec file from aero.sors would give you a magnetic crs of 159. Ity turns out the current magnetic variation of the airport is 3.6 degrees E and not 2). So do not panic if you still experience a difference between the charts and the crs evne after updating the magvar.

aero.sors also has an extremely useful tool called AIE (Airport Inspector and Editor) where you can load each .bgl file for each airport affected and allows you to actually see the ILS frequency and crs encoded in the file, especially the ILS crs implied by the updated magdec file. And you can edit it if you need (for example frequencies, identifier,etc).


One important thing to consider is that each airport also has its own magnetic variation encoded in the .bgl file (however up to date it can be or not) but the simulator does not use that to calculate ILS crs that A/P follows. it uses the magdec.bgl data at the localizer position which is contained in the scenery/base P3d folder (which is the one aero.sors would update).

Mark has mentioned a few months ago that the server now reads directly the magdec.bgl data to inform FMS and A/P tracking of ILS crs so you also want to make sure that the magdec.bgl file you have in p3d matches what you see in the sim-a avionics navigation folder.

Hope this helps a bit, I really banged my head on this for a few days until I finally understood what really goes on here...
Andrea
Jetmax 777
FDS-MX-OH -- MCP-MX

Banananav
Posts: 99
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Location: 5nm West of RAF Cranwell

Re: ILS Problem

Post by Banananav »

Hi Andrea
Where did you find that the mag variation at an ILS or VOR was taken from the Magdec.bgl file and not the specific navaid bgl file ?
I had always (wrongly) assumed it was the latter case.
Rgds
Chris
Ps - Rigilkent ?
Chris Finn

Jetmax 737-800 & TQ
MX MCP & EFIS
P3D 4.5 HotFix2
S-A 1.966
FSUIPC 5.155

Rigilkent
Posts: 85
Joined: Wed Aug 02, 2017 11:31 am

Re: ILS Problem

Post by Rigilkent »

Hi Chris,

A lot of trial and error (first), and then thanks to Herve Sors that put it all together for me.... That's when it all started to make sense.
Look especially at points 3 AND 4.

https://www.aero.sors.fr/documentation/ ... dingMV.pdf

PS: Rigilkent is just a nickname I had since I was a kid.

Andrea
Andrea
Jetmax 777
FDS-MX-OH -- MCP-MX

Banananav
Posts: 99
Joined: Thu Oct 08, 2015 11:46 am
Location: 5nm West of RAF Cranwell

Re: ILS Problem

Post by Banananav »

Thanks Andrea
That all makes sense - so why the navaid bgl includes variation is irrelevant.
I wondered if you were a fellow (Astro) navigator
Rgds
Chris
Chris Finn

Jetmax 737-800 & TQ
MX MCP & EFIS
P3D 4.5 HotFix2
S-A 1.966
FSUIPC 5.155

memeyer
Posts: 49
Joined: Tue Mar 27, 2018 4:29 pm
Location: Gardner, Kansas

Re: ILS Problem

Post by memeyer »

Thanks to all for their quick response. I spent all yesterday checking flights specifically into KDEN. The problem seems to be SOMEWHAT alleviated by Steves, answer. I definitely needed to run the software that helped magnetic variation. I probably wasn't as accurate in my description of the problem. Put another way it seems the the ILS frequency from the airport was NOT STRONG enough to keep the plane on the Glide-path. The Glide-sloop always seems to hold all the way to touch-down. I am still experimenting and will try the next suggestions. Thanks again to all!!!!

Rigilkent
Posts: 85
Joined: Wed Aug 02, 2017 11:31 am

Re: ILS Problem

Post by Rigilkent »

Yes.
The nickname comes from a passion for astronomy since I was little :)
Andrea
Jetmax 777
FDS-MX-OH -- MCP-MX

Rigilkent
Posts: 85
Joined: Wed Aug 02, 2017 11:31 am

Re: ILS Problem

Post by Rigilkent »

[quote=memeyer post_id=41650 time=1589052691 user_id=2211]
Thanks to all for their quick response. I spent all yesterday checking flights specifically into KDEN. The problem seems to be SOMEWHAT alleviated by Steves, answer. I definitely needed to run the software that helped magnetic variation. I probably wasn't as accurate in my description of the problem. Put another way it seems the the ILS frequency from the airport was NOT STRONG enough to keep the plane on the Glide-path. The Glide-sloop always seems to hold all the way to touch-down. I am still experimenting and will try the next suggestions. Thanks again to all!!!!
[/quote]

The tool I mentioned (AIE) by Herve Sors has an ILS editor tool that you can use. You can actually import the info from the latest airac and check how they differ from what is encoded in the airport .bgl files, and you can also 'extend' the beam of the ILS glideslope. Or, the tool itself would calculate it automatically basically on the location of the antenna.
Little advanced but can help... (the tool would always make a the airport .bgl file backup so you can always revert to the original one if needed).
Andrea
Jetmax 777
FDS-MX-OH -- MCP-MX

MichaelYSSY
Posts: 748
Joined: Tue Jan 06, 2015 11:04 pm
Location: Sydney - Australia

Re: ILS Problem

Post by MichaelYSSY »

Hello All.

A lot of discussion with regard to Magnetic Variation and ILS.

With the following note in that linked document.

(3) Not being correctly aligned on a runway axe while on a final ILS approach with a centered LOC needle is NEVER the result of any “wrong” magnetic variation. It could be due to (i) either an “offset” ILS (and this is indicated on charts) (ii) or a wrong coding of localizer antenna position and/or localizer true course by reference to runway axe.

Chan someone please explain to me HOW Magnetic Variation will influence ILS alignment of the aircraft?

In item 4 it refers that in the flight simulator that the ILS is coded using TRUE Course not Magnetic.

4) ILS localizer course (see also Note 3) In the simulator, position of aircraft relative to ILS localizer is modeled and displayed on VOR receiver from aircraft geographical position, localizer antenna positionand localizer true course.

Thanks
Michael
SSTD 737
Sim-Avionics v1.96
P3D 4.5/5.0 HF1
FSUIPC 6.0.8

omera60
Posts: 157
Joined: Tue Nov 18, 2014 9:37 am
Location: Istanbul

Re: ILS Problem

Post by omera60 »

Hi All,

Just saw this, thought it might help...

https://forum.simflight.com/topic/89050 ... epar3d-v5/

Best,
Omer
Image

Banananav
Posts: 99
Joined: Thu Oct 08, 2015 11:46 am
Location: 5nm West of RAF Cranwell

Re: ILS Problem

Post by Banananav »

Hi Michael
You are quite right - ILS aerials are in a fixed, true, alignment and the needles just indicate where you are relative to that alignment.
The point Andrea makes about keeping the magdec.bgl files up to date and the same in the sim and sim-avionics folders is for consistency of heading and ILS course as published in, say, Navigraph, in the FMC and on the compass.
Totally different for a VOR where the variation has to be correct for the radials to be correct.
As another rabbit hole, what does this mean, if anything, to reading the HSI ?
Rgds
Chris
Chris Finn

Jetmax 737-800 & TQ
MX MCP & EFIS
P3D 4.5 HotFix2
S-A 1.966
FSUIPC 5.155

MichaelYSSY
Posts: 748
Joined: Tue Jan 06, 2015 11:04 pm
Location: Sydney - Australia

Re: ILS Problem

Post by MichaelYSSY »

Hi Chris

Thank you. Yea in a way Simulators are sometimes more complicated creatures that real aircraft setups.
There are so many different programs and they all need to be somehow synced and talking to each other.

One day there will the perfect setup, one where all the systems will be working in tune and without issues (that's my dream)

Cheers
Michael
SSTD 737
Sim-Avionics v1.96
P3D 4.5/5.0 HF1
FSUIPC 6.0.8

memeyer
Posts: 49
Joined: Tue Mar 27, 2018 4:29 pm
Location: Gardner, Kansas

Re: ILS Problem-UPDATE

Post by memeyer »

To ALL the replies:
Thanks again. It seems that I have a problem with my rudder pedals. After all of the updates that I made, I was still having the Glidepath become inactive as I got closer to the airport. I had always tried to get my feet on the rudder pedals without moving them. BUT, it seems that if I totally keep my feet away from the pedals UNTIL actual touchdown, the ILS holds right on until touchdown.
For what it's worth to all. I may be the only one having this problem in the manner I described it. Thanks again for all of your repsonses!!!


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benjiminus
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Re: ILS Problem (Resolved)

Post by benjiminus »

I have the problem of my CDU is the only thing that has the wrong ILS heading. When on final, I have to look at the PFD to get the correct heading. I also use Aivlasoft efb. The efb and PFD seems to pull data from the same place, however, my CDU is never correct. I've ran the make runway program and my CDU is even further off than before running it. KMIA Rwy 27 heading of 272 on the PFD (which is correct) but CDU says it's 276. While on downwind, CDU actually changes to 277 and then back to 276 when I turned on final.
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