- Is AFIS regulated in any legal document (ICAO, Eurocontrol, AIPs, ANSPs...)?
In Sweden there are national regulations for education of AFIS
I learnt flying at an aerodrome in Sweden which was ATC until, I believe 17:00 LT, when it became AFIS. We had scheduled IFR traffic, albeit only a few, after that time. My flight school was continuing operating as normal but, IIRC, the AFIS-operator didn't want more than 2 in the traffic circuit (local procedure I believe).
The setup around AFIS aerodromes in Sweden, dunno if same in Spain, is TIZ/TIA. Class G airspace, no separation services provided. So I believe it's see-and-be-seen.