The real issue is not VFR versus IFR. The real issue is whether you have the clearance to enter CAS. Normally, on an IFR flight plan filed via Eurocontrol, this comes in the form of an “IFR clearance”.
Often, one is in IMC before getting the IFR clearance but that is of course illegal. But nobody can tell because nobody can see you. What you cannot do is enter CAS – because they can see you on radar. I am just being practical 
The only time you have the said clearance immediately on departure is
Yes, you can get clearance on the ground but that doesn’t mean you’re IFR from the very beginning of the flight if departure airport doesn’t feature SID. If you takeoff from VFR airport you can only start VFR until IFR pick up point (however it’s defined – be it some intersection, navigational aid or just reaching cleared altitude)
Sorry Emir, but that is generally all wrong. It might be the Croatian implementation (and it is more or less the German implementation), but it is not according ICAO. See the UK or France (as big nations), who follow ICAO guidelines and allow IFR in Golf, anywhere.
A SID is absolutely not required for departing IFR.
One can “pick up IFR” (only a clearance can be picked up, not a flight rule change) even when one was previously IFR (wothout a clearance).
Emir wrote:
Yes, you can get clearance on the ground but that doesn’t mean you’re IFR from the very beginning of the flight if departure airport doesn’t feature SID. If you takeoff from VFR airport you can only start VFR until IFR pick up point (however it’s defined – be it some intersection, navigational aid or just reaching cleared altitude).
I can’t imagine that you can get clearance on the ground on VFR airport (or any airport that you takeoff VFR) which clears you to start IFR immediately after takeoff. It’s more likely that you’ll get something like “clear visually to x, climb to altitude y, QNH xxxx, squawk yyyy, contact zzzz at xxx.yy”.
Likely or not, that’s what happens. Typical ATC communication at my home airport (VFR only, uncontrolled). Uppsala TWR is a nearby ATC unit.
Uppsala TWR, SE-XXX on ground Sundbro, activating IFR flight plan to (destination)
SE-XXX, Uppsala TWR, Cleared to (destination) via flight plan route, (level), squawk (code), QNH (setting)
Peter wrote:
Often, one is in IMC before getting the IFR clearance but that is of course illegal. But nobody can tell because nobody can see you. What you cannot do is enter CAS – because they can see you on radar. I am just being practical
What are you saying? It is illegal to be in IMC before getting an IFR clearance and before entering CAS?
It is also very rare in the UK that any Class G airport gives you an IFR departure clearance which extends into CAS, but it is not impossible. I have heard that Oxford and Coventry do it. I don’t know if Biggin Hill does it; they do publish “standard departure routes” (which Jeppesen call “SIDs”, to the consternation of all pedants who correctly say that any SID must be in CAS and OCAS you can have only an SDR 
) but they are Class G, so you may be working like a one armed bandit at 2400ft to call up Thames Radar to get the proper clearance.
It is illegal to be in IMC before getting an IFR clearance and before entering CAS?
It is legal in a country which allows non-radio IFR in Class G (the UK)
I will leave it to others to throw in a few options here
They have had some interesting cases in the USA, where somebody got busted for entering IMC in Class G (there were witnesses and in the USA that seems to be enough). They got busted not for flying IFR in G without an IFR clearance (because a “clearance” is meaningless in Class G) but for not having filed an IFR flight plan.
Back to my original question / thought …
When I get back there I will try to find the proper answer by talking face to face to the people at Sabadell Tower. I will become a local so I should know them and they should know me a bit. I will report when I got some answers.
My current thought is that going into the hold over SLL might actually be a good idea. They have class D up to 3500’ and then class A from there on. If the weather is bad – I don’t know yet how frequently that actually happens there – one might ask for special VFR for the takeoff and go into the hold over SLL. Sabadell seems to have radar. The big question is whether they will be willing to issue a clearance for going into the hold when one will enter IMC shortly after takeoff. They usually say “cleared takeoff runway 13. Fly 3 miles on runway heading, then turn right and hold over SLL”.
There might be a bit of corkscrewing going up in the hold but that is probably better than not being able to leave at all. Obviously the question is still how far special VFR might go …
On how many day´s you have so bad weather at Sabadell that you need a special VFR? I would skip the holding for a flight to the North. It is just a waste of time an fuel.
Biggin gives no clearance to enter CAS, always below and the SID, London control give you the clearnce to enter CAS but most not much more. Last time, was the first time, where I get a full “airway joining clearance” in the past it was only “climb FLXY”.
Biggin gives no clearance to enter CAS, always below and the SID, London control give you the clearnce to enter CAS but most not much more. Last time, was the first time, where I get a full “airway joining clearance” in the past it was only “climb FLXY”.
Any clearance from London Control is a full IFR clearance and you can forget CAS at that point. But only a local pilot is going to know that.
This stuff can get tricky.
The bottom line is that even under IFR you need to look up the said airport on a VFR chart and check if it is in CAS. In reality few bother to do that on mainland Europe, but it will get you into a big problem in the UK because once London Control give you a descent out of CAS, you are not allowed to re-enter CAS. Usually, nowadays, they actually tell you that.
@Stephan_Schwab: Following the whole discussion until now it seems like you can file IFR (instead of Z) and directly take off IFR and not bother about getting a clearance later on. Except the airport does not allow IFR (see comments from achimha and tomjnx).
