Hi,

I would like to report a problem with Approach procedure read by BGL files: many procedures refer to terminal waypoints (i.e. waypoints that exist in an airport record) in contrast to non-terminal waypoints (i.e. present out of the airport record). But names of terminal waypoints are repeated multiple time for all airports. Example many airports have points named "CI07"... even in the same icao_region. LNM only seems to look for the icao_region and the waypoint name. So if a procedure for, example, LFPO links to "CI07", LNM looks for this CI07 in the whole "LF" icao_region. Multiple are found, for example I have one also in LFPB. LNM uses the first found alphabetically. That is a problem as the wrong WP is used, a wrong procedure is displayed and I guess this also reflects into a wrong export.

I guess the solution would be to also track the airport name for terminal waypoints.

 

Sorry, but I need more information. What simulator? MSFS, FSX or P3D?
Do you have a Navigraph update installed for MSFS and/or LNM? What AIRAC, if applicable?
What is the selection in LNM "Scenery Library" -> "Navigraph"?

Can you name a concrete procedure where this fails? I see no issues with ILS 07 FF07 (I07) at LFPO, for example.

LNM resolves procedure waypoints depending on different criteria. Some simulators provide coordinates, some provide regions and some the airport ICAO. LNM uses whatever is available.

Alex

fsx db and procedures. Navigraph disabled. I found a couple of cases, but all with addon scenery, so cannot immediately point out to a case. Question is: for FSX DB approach, how are terminal waypoints specified in the procedure selected? I have the feeling only by region and icao_ID. The criterion "Airport ID" is ignored.

 

FSX does provide, waypoint ICAO, region and airport ICAO for waypoints. LNM resolves these on the fly when loading a procedure since it is too complex. This means that this will not happen when loading the scenery library.

Looking at the code LNM uses the waypoint ICAO, region and type (VOR, NDB, etc.).
I think I omitted the airport code in the search since it was unreliable. Even more in add-on scenery.

No problem with FSX stock data for LFPO I06. You have a concrete example for a stock airport?

Alex

 

 

 

 

Need to find it.... not easy, because i need to find a duplicated navaid name in the same region actively used in a procedure of another airport of the same region....

But it's strange: I created deliberately a faulty case (added 2 procedures on 2 airports with the same terminal waypoint name), but ... but.... it is correctly found. No idea what happened with my addon LFPO that found the navaid of Le Burget.... 😞 Maybe a problem with that scenery. I will dig more and if I find another problem I will flag it to you. Sorry for the inconvenience

 

 

3 minutes ago, arrex said:

Maybe a problem with that scenery.

What I suspect.🙃

LNM actually fetches the duplicates in one region and then gets the one which is the nearest to the airport. I'd not expect a 100 percent working solution due to the insane complexity of procedures.🤷‍♂️

4 minutes ago, arrex said:

Sorry for the inconvenience

No problem at all!

Alex

16 hours ago, albar965 said:

LNM actually fetches the duplicates in one region and then gets the one which is the nearest to the airport. I'd not expect a 100 percent working solution due to the insane complexity of procedures.🤷‍♂️

 

 

aaah, that's the problem indeed! Duplicate waypoints on 2 nearby airports. I made an extra test: LFPB RWY 06 comes in my scenery with a CI06 that is on the extended centerline of LFPB at about 10 NM further.... and that makes it 5.7 NM from LFPO. Point CI06 of LFPO is 9 NM from LFPO, so the algorithm picks up erratically the one of LFPB as the closer of the two.

Indeed is a marginal case, and happens twice for that airport (CF06 and CI06 for Vor and ILS approach)....unlikely of representing a significant problem. I solved it by renaming two points in LFPO.

Out of curiosity, why using the distance criterion? Wasn't reading the airport record easier? I ses in the "navaid information" page that the referring airport, for both, is correctly identified....

 

I'll have a look at the code and will try to use the airport ICAO for the search as well. If this does not give any results I can still fall back to empty airport ICAO.

But the waypoint names have to be unique within an ICAO region. X-Plane requires this, for example. I'm sure this is also an requirement in the official ARINC data.

Alex

For FSX and P3D the unique ICAO is actually a 12 character string. Unified for all waypoint types.

The FSX+ unique identifier is:

char 1 -> Type (A= airport, V = Vor ....)

char 2-3 -> ICAO Region

char 4-7 -> ICAO of the referring airports (typically only present in terminal waypoints)

char 8-12 -> ICAO identifier

So an intersection LAGON can be: WLILIPQLAGON if it is a terminal waypoint belonging to LIPQ or WLI____LAGON if it is a navigation intersection (unique within region "LI")

 

Typically. terminal waypoint are not present normally in any real database, but they are there to help drawing the approach procedure.

Probably what you suggest is the best: if you have a record for airport, use this, otherwise you fall back on distance. Should be working then.

 

13 minutes ago, arrex said:

Typically. terminal waypoint are not present normally in any real database, but they are there to help drawing the approach procedure.

They are certainly present in official nav databases but are marked as terminal and have the additional airport ICAO.

14 minutes ago, arrex said:

For FSX and P3D the unique ICAO is actually a 12 character string. Unified for all waypoint types.

Never seen the 12 character string notation in FSX/P3D. For me it is a combined key consisting of ICAO, region, type and maybe airport ICAO.

Alex

Quote

They are certainly present in official nav databases but are marked as terminal and have the additional airport ICAO.

Some of them yes.... but FS abuses of them.... many do not exist at all and are just fictitiously created....

 

This is the best doc around for FS9/FSX/P3D Database and GPS dll:

GPS Guidebook

Pag 12 on the ICAO format of MS simulators....

But probably we are deviating here... after all this 12 character icao is just the sum of type, region, airport icao and icao identifier. So if you read those elsewhere separately, you are already doing the job, irrespective on how the internal FS database can be queried....