Is there something like a register of frequencies for airfields/airports in Europe? I am building a VFR flight planner and would be interested to autofill a form with the frequencies dependent on the given input data. Is there something like a database?
Try https://www.ead.eurocontrol.int/eadcms/eadsite/index.php.html . It is not a database but you have access to all AIPs from members of Eurocontrol .
For Germany I found a list of frequencies at Spitz Online (a private site of an enthusiast).
It covers almost 700
airfields frequencies but I'm not sure how accurate it is.
For instance, I checked FRA/EDDF against OurAirports and noticed some differences.
He also lists different frequencies for the different purposes (APP, TWR, GND, ...), e.g. MUC/EDDM is listed with 33 (!) frequencies. But – as a programmer – you might be able to parse the output of OurAirports. As far as I can see, the
http://ourairports.com/airports/<ICAO_CODE>/pilot-info.html#comm and the returned HTML page
lists the frequencies in
<section id="comm" class="tab-pane fade">. But you would have to parse
that yourself and I'm not sure whether they would really like that.
I again visited OurAirports and found their data downloads page. It's accessible from the menu. They say:
For more intense work, we have a CSV-formatted data dump of all our airports, countries, and regions, which we update every night. You can download these files […] You can even use them to set up your own, competing airport web site if you'd like! We'd love you to give us credit, like we give credit to our sources, but you're not required to.
Right now the files have zero size (already indicated on that page) but when I looked yesterday they were all good and had reasonable sizes. The .csv with the frequencies had ~1.5 MB IIRC. So if you trust them, you could fetch the information from there. No need to crawl and parse their website. Note that this is not an “official” source but merely like a wiki where anybody who's signed-in can add and change DB entries.