I've checked the frequencies around Zurich between SkyDemon and the official ICAO-map of Switzerland, and it seems to be 100% in sync. In that case, the official plates are suggesting an inappropriate frequency. Perhaps Skyguide wants you also to call FIS frist upon TMA crossing, however, this doesn't make any scence, since Zurich Terminal does this job for VFR-traffic. As far as I understood from Skyguide, the Terminal controller sits direct next to the departure and arrival controllers. Zurich Information however ist located at another office, which makes a call and further coordination necessary. They also don't have direct access to flightplans, which makes everything more complicated.

Regarding Germany: Would it be possible to display the Radar-frequencies from IFR-plates to the associated class C and D airspaces on the map? I use this IFR-plate "workaround" every time when I want to cross a local class C or D (non-CTR) airspace in Germany. Asking FIS is also an option of course, but on bussy weekends, the FIS-frequencies are overcrowded, limiting the chances of a clearance.

Unfortunately, I couldn't make it to the AERO in Friedrichshafen due to a very busy schedule at my work. I even forgot to mention it before and forgot about all my other open topics. My appologies for that.

I've figured out that "AirNavPro" (ANP) displays all the Approach frequencies for the German (non-CTR) TMAs, like Langen Radar "118,750" and "135,350" for Cologne/Bonn. It would be great to have this information also in SkyDemon, so pilots can contact the appropriate ATC-unit directly, instead of using FIS, which costs time and decrease the chances of a clearance. Did the DFS say something about this already to you guys? The frequencies are mentioned within the IFR SID and STAR-charts.

Furthermore, I've found out that SkyDemon does not display any frequency for general class C in Switzerland, which would be very usefull to get an "on op" clearance for the Alps. For the western part, this would be "Geneva Delta" on 119,175 and for the eastern part, this would be "Zurich Delta" on 119,225. The boundaries between Zurich and Geneva for Delta are the same as for Information (FIS).

There are now two separate matters under discussion here, which is confusing. I will ask my colleague to look into the Swiss airspace issue and make contact with the authorities there to confirm the division. Class C in Switzerland is divided into northern and southern parts, quite the opposite of how the FIS sectors are divided.

I have asked the DFS again if they will officially define the correct frequencies for penetration into the enroute class C/D airspace.

Are there any updates regarding this topic?

Regarding Switzerland: The frequencies for General Class C in Switzerland are also still missing, this should be "Geneva Delta" on 119.175 in the Geneva airspace and "Zurich Delta" on 119.225 in the Zurich airspace (same boundaries as FIS). FIS is only responsible for airspace E and G in Switzerland, for C (non-TMA) it is Delta. This is also described in the AIP ENR 2.1.

Furthermore, there is an issue with the "Information" frequency for LSME, LSZC and LSMA. This just an information frequency for airspace activation, just like an ATIS, which tells you what airspace is active or not. You cannot make a call on that frequency and its certainly not an AFIS. It's now mentioned as "Buochs" for LSZC, "Emmen Information" for LSME and "Alpnach Information" for LSMA, but it should be called "Airspace Information" or something similar, since it is one frequency for all named aerodromes. This takes me to the next error: "Kägiswil Information". There is not an AFIS-frequency for LSPG. Before departure, pilots should monitor the airspace activation-frequency to check if the airspace of Alpnach is active or not, and then the pilot should call Alpnach Tower for clearance OR make blind-calls on the Alpnach Tower frequency for Kägiswil. In my opinion, "Kägiswil" 128.475 would be sufficient for LSPG.

Last but not least, Meiringen (LSMM) and Dubendorf (LSMD) have only "Tower" as radio-callsign, which should be "Meiringen Tower" and "Dubendorf Tower" of course.

They're not officially documented anywhere, which is a problem because even if we take it on faith that they work, our data is at risk if they ever change. We rely heavily on the AIP update process to ensure that changes to airspace design are correctly represented in our data when they occur, which is why we try to never add our own interpretation on top of the official data.

Yes, I have done the work myself on the Swiss delta frequencies this morning and you should see that take effect in tomorrow's chart update.

Germany: Yes, they are documented, however, only on the IFR plates of the corresponding airport. I know, this is really tricky from the DFS, but would it be possible to read out that information? For example class C for Köln/Bonn, the Arrival/Departure charts reveal the TMA-frequency: "Langen Radar" on 135,350. For Dortmund, this is "Langen Radar" on 125,225 and for Stuttgart, there are two frequencies: 125,050 and 119,200. Just check the SID and STAR charts. These frequencies are also shown correctly in AirNavPro, so I assume that it would be possible to get them also into Skydemon? Would be a great help!

Switzerland: Sounds great, I really appreciate that! :-)

Possible yes, but that doesn't make it sustainable. If we did as you suggest we would have to check all new IFR approach plates for changes to the frequency for class C/D airspace whenever they were released. That would not be very good value.

Other products are indeed available, but as has been shown over the long term, their data tends to be ill-maintained.

Good to know. I was in the expectation that once you have configured the settings, you could read out those frequencies automatically for each upcoming Skydemon chart.

Nevermind, I've found the frequencies also in the German AIP ENR 2.1, starting at page 36. Could that help to maintain the data in the SD-charts, or would that still mean too much manual work for each update?

Yes, the definition of the airspaces are maintained at the beginning of the document. The radio boundaries however, are maintained starting at page 36. Those boundaries are different from the TMA/CTAs and also include general class C, airspace E and G. IFR traffic in Germany never talks to FIS, so they are always in contact with a Radar-Frequency. At night, when FIS is closed, also NVFR traffic talks to Radar.

For example the Situation around Cologne from ENR 2.1:

Airspace classification for Köln/Bonn has been done at page 9. Radio classification has been done at page 67 (EDGGDKA).

For the radio, the lower limit for the boundaries of "EDGGDKA1" is GND and the upper limit is FL145, which already is general class C, however in between, it is class C TMA. The same counts also for "EDGGDKA2" from GND to FL195 and "EDGGDKA3" from GND to FL105.

Another example: The area around Dortmund and Paderborn. The airspace D (TMA) is maintained at page 23 and 24, the radio assignments are maintained at page 72 (EDGGPADL), including the boundaries for the frequencies (EDGGPADL1 - EDGGPADL5).

I hope this brings some light into the tunnel. The DFS makes it really complicated, but the information is there.

I've noticed that some of the TMA frequencies in Switzerland does not match with the correct ATC-unit. For example, around Zurich, SD mentions "Zurich Information", but this is only the FIS-frequency and they can't give clearances by themselves. For TMA crossings "Zurich Terminal" is the correct ATC-unit to contact in TMA-airspace around Zurich for VFR-traffic in class C. For crossings within the non-TMA and non-CTR airspaces (class C and D), "Zurich Delta" is the correct ATC-unit. They give for example clearances to cross corridors and in general class C airspace above FL100/FL130.

In Germany, the non-CTR airspaces in class D and C doesn't have published frequencies for VFR-charts at all, but they are mentioned within the IFR-arrival/departure charts as Radar frequency. For example around Suttgart, this would be "Langen Radar" on 125,050 or 119,200 and around Cologne/Bonn, this would be also "Langen Radar", but now on 135,350. The problem here is the German ATC-company "DFS", which want to force VFR-pilots to contact FIS first prior to cross airspace class C or D.

Regarding the original topic of this thread, the official line from German authorities is that pilots should contact the relevant FIS frequency if they wish to gain penetration into any of the enroute C/D airspace.

I checked a couple of the airfield frequencies you mentioned and it appears we are showing what the AIP entries for the airfields shows, which is our policy. We would consider it an error if the frequencies shown in SkyDemon differed from the official source information usually in AD section 2.18.

The frequency we have for Kagiswil differs from the frequency you give. Are you saying the frequency is wrong or the callsign is wrong?

I agree the callsigns for LSMM and LSMD could be better, I will forward this along.

Would you mind creating separate threads for separate issues? It helps us greatly when it comes to investigating them all.

Sorry, the split between airspace definitions and area control definitions is so jarring that it's a complete non-starter for us. We'd be trying to use that data for something it isn't strictly supposed to be being used for, by creating a weird mapping that isn't entirely clear, and expecting our data maintainers to keep on top of it, error-free, when the country itself wants us to use the FIS frequencies for any VFR pilots wishing to gain access to those pieces of airspace.

Our best bet is to campaign for the authorities to change that recommendation, if you wish SkyDemon to advise different frequencies than the FIS frequencies.