Sign in to follow this  
dnunes

ILS at Genoa

Recommended Posts

I have found an error in the Genoa ILS (ID=GSE) similar to that in Nice: the GS is at the same location as the localizer, resulting in a wrong glidpath. The DME also shows the distance to the localizer and not to the runway threshold, as it should.While I had no problem in correcting the error in Nice, I am not able to make the correction in Genoa. I get the correct coordinates for the localizer and GS using AFCAD, which shows the correct location, and use them in EasyNavs to modify the bgl file.The problem is that the correction is not effective, as I always get the same glideslope and DME error.Has someone an explanation for this? I would be grateful for any help.Best Regards,

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Domingos:I fly that approach frequently in FS 2K2 and according to my Jeppensen Simcharts, the localizer is off-set slightly to the south of the Initial Approach Fix (IAF) CMO NDB. The glideslope brings you only to the Missed Approach Point (MAP), which in the case at Genoa (LIMJ), is to the displaced threshold only and not to the actual runway numbers. A common misconception, this is true of most ILS approaches, in that they will only bring you to the MAP, not the numbers. If you're not visual by then its a go-around.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

Share this post


Link to post
Share on other sites

Thanks Alex for your reply. I still feel there is something wrong. The DME is at the same location as the GS, i.e. at the displaced threshold. My Jeppesen chart says that the ILSDME reads zero at this point, what would be normal. However if I taxi my aircraft to that position the DME reads 1.6 miles. This is the location of the localizer at the far end of the runway! The distances to GSE, in the Jeppesen chart show correctly the distances to the displaced threshold, what is correct, as the DME is at that location, but that is not what I get when flying an approach.If you have EasyNavs, could you please send me the configuration you have for GSE? I think that could help.Thanks for your help.

Share this post


Link to post
Share on other sites

Domingos:Can't recall if I still have EASYNAVS Installed. I had to make a navaid correction once and read about the program so downloaded it, but may have reamoved it. Let me check and I'll get back to you. More fun for me at least, let me shoot the appraoch and get back to you.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

Share this post


Link to post
Share on other sites

Domingos:OK, I just landed at SESTRI, a 1.3 hour IFR flight from Toulouse Blagnac LFBO. Take a look at the photo. My DME says 2.3 to land, and of course it is much closer, so you're right, it seems odd. Second photo, very short final, DME still reading over a mile. I may have to relocate that DME transmitter with EASYNAV like you say. I'll keep you posted.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

Share this post


Link to post
Share on other sites

Dear Alex,You are in the same situation I have found: on the second shot you are almost at the threshold and the DME reads 1.6 miles (this is the far end of the runway, where the localizer is installed). On the other hand the GS shows you are very high: although the Jeppesen chart says the GS is erroneous below a certain point, I do not believe FS can simulate this, as there is no special configuration for the ILS.In case you manage to obtain the correction, please send me the eurswils file so that I can compare it with mine.What puzzles me is that I found the original file was wrong, with the localizer, GS and DME at the same co-ordinates. I changed the GS and DME to the location indicated by AFCAD, which seems to be correct, and the result was exactly the same!Best Regards,

Share this post


Link to post
Share on other sites

Domingos:Look carefully at my HSI - the GS is correctly showing me low, but in relation to the VASI lights, I'm not that low! Could FS 2K2 be treating this as a backcourse approach? I doubt it, because the movement of the localizer needle with respect to my aircraft was not opposite like it would have to be on a backcourse localizer approach.Very confusing, but I do like the approach.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

Share this post


Link to post
Share on other sites

Alex,That is true, according to the GS you should be much higher, but the VASI shows that you within limits.Next weekend I will try again to make some tests, trying to understand what is happening. There seems to be something strange with this airport. As I have told in my first post, the Nice airport had a similar problem. I corrected it and now it is OK.As a further test I installed an ILS in an airfield, near the Lisbon airport, which of course has no ILS in real life. I followed the common procedure, i.e., I located the navaids with the help of AFCAD and used the coordinated provided by AFCAD to locate the localizer, GS and DME using EasyNavs. Everything worked nicely: the DME shows zero when I am at the threshold and the GS brings me to the numbers in the runway. This assured me that I can locate correctly the navaids. Surprisingly that seems not to work in Genoa!I will let you know if I make some progress on this subject.Best Regards,

Share this post


Link to post
Share on other sites

Domingos:Keep me posted on your progress with Genoa, as I really like flying there. With the new mesh sceneries, the mountains are just lovely on approach, and when turning inbound the city lights on the coast almost make me feel like I'm there.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

Share this post


Link to post
Share on other sites

"On the other hand the GS shows you are very high"On the contrary, it shows he is very low in relation to the GS, which leads me to believe that you are correct, in that the GS transmitter is not located correctly, as you suspected in your initial message. It looks like that in the scenery file they have located the GS transmitter together with the LOC transmitter, at the far end of the runway.Stamatis

Share this post


Link to post
Share on other sites

Stamatis:Tikanis from Minneapolis, MN, USA. Domingos tried to relocate the GS and localizer using AFCAD and/or EasyNavs, but was still getting the same DME readings on short final.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

Share this post


Link to post
Share on other sites

Eimai poly kala! :-)"Domingos tried to relocate the GS and localizer using AFCAD and/or EasyNavs, but was still getting the same DME readings on short final."Yes, I understood that reading his messages.But the GS must be misplaced in the scenery, for sure. How can one fix this is another matter...I am not aware of how FS2K2 handles the DME transmitter in the scenery. Is it co-located with the GS or the LOC transmitters?Stamatis

Share this post


Link to post
Share on other sites

Good question.....I'll try and take a look at it tonight, though I doubt I'll fare any better than Domingos.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

Share this post


Link to post
Share on other sites

Dear Alex and Stamatis,The DME can be located anywhere, as you can define its co-ordinates independently of the localizer and GS. When you have an ILSDME you usualy locate it at the GS.What I can tell you is that something strange is happening with this particular ILS. As I said before, when I first looked at the problem I found a wrong location for the GS and DME: both were at the localizer co-ordinates. Then I corrected the co-ordinates for the GS and DME, and amazingly nothing changed!As you can have the aircraft position shown in AFCAD, I even checked that that the co-ordinates provided by AFCAD were consistent with F2K2. I will work on it a little more next weekend.Best Regards,

Share this post


Link to post
Share on other sites

Domingos:I tried playing with the coordinates of the DME in AFCAD too, using my airplane's position in AFCAD,to no avail. I even repositioned the localizer antenna from the far end of the runway to the threshold, also to no avail. Something is definitely weird here, and I suspect its a missmatch in coordinates somehow, somewhere. My next idea is to constantly relocate the DME further and further away from the threshold until I get 0 miles indicated on my panel at the numbers on final. I'll let you both know what I find.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this