Yes, flying IFR in controlled airspace (as well as VFR in B/C/D airspace) certainly has advantages. :-)
That (the VFR bit) is another tricky one…
ATC are reluctant to issue vectors to VFR traffic, because VFR traffic cannot be compelled to enter IMC.
That may be why so many ATC sectors do not allow VFR in CAS… no way to control it once it is in there.
If going Eurocontrol IFR, you can fly only between airports which have sids/stars (which more or less implies they are in CAS).
There are lots of IFR airports without both SIDs and STARs which are inside CAS. You can perfectly well file Eurocontrol IFR flight plans to and from these places. You can even file Eurocontrol IFR flight plans to and from non-instrument airports. It’s up to the national ATS to decide.
You can even file Eurocontrol IFR flight plans to and from non-instrument airports. It’s up to the national ATS to decide.
I think that’s the most accurate statement. You can file Eurocontrol to/from anywhere the Eurocontrol computer allows you to – and the Eurocontrol system does what the national ATS tells it to: In Germany, you need an Instrument airfield (which means CAS), in the UK you can file IFR from your back garden (as ZZZZ).
Outside the UK, that flight plan will normally get you unquestioned access to controlled airspace and a radar service. In the southern UK (Scotland seems to be different), that flight plan may or may not get you access to controlled airspace and a radar service. Depending where you are going from/to, you might have to treat some part of the flight like a Y or Z plan – except that you can be IFR during that Y or Z part if you wish.
There are lots of IFR airports without both SIDs and STARs which are inside CAS.
Not if MAX DCT = 0
To connect to an airport without a SID or a STAR, you have to use a DCT, which is not possible if MAX DCT = 0.
To summarize:
1) Departure Clearance (or any clearance): valid only if you remain in CAS and not altered.
2) D/R/P Airspaces: concern can be delegated to ATC in CAS and to pilot OCAS.
3) Vertical FL adjustments to make a plan work don’t need to be flown. However, you run a risk that you won’t be able to satisfy IFR loss comms procedure if NORDO.
4) In UK, by exited CAS, one runs the risk of having their FP dropped and upon re-entry, may need to prompt ATC on list of next waypoints.
5) ATCO’s are all aware IFR routes generated for SEP aircraft are because of routing ‘errors’
6) OCAS: you can deviate from the FP without ATC permission like VFR flying. FP OCAS is more of a ‘notification’ than a ‘control’ value.
DMEarc
hey just to clarify before this gets out of hand….
my previous post was about my case (i.e. ELLX to LFJL) and the MAX DCT restrictions come out of RAD APPENDIX 5 for airspace LF (France)
anf if you read all the message the MAX DCT = 0 is for AD with SID/STAR, all others have a MAX DCT of 30 or 50 NM so you can file IFR departing OCAS in G class.
As for CAS/OCAS, I expect at least the same level of service in IFR OCAS as I would have VFR. For France (where i fly mostly for now) in VFR Class G, if they can, FIS will warn you about P/R/D or other NOTAM areas and you can ask them lots of information (weather, frequency, FPL closure or opening, …)
And I’d also expect my flight plan to be routed to every CAS on my way, regardless of whether I may fall OCAS on the way.
But apparently not happening in UK, so maybe I’m a bit naive (or lack experience) 
To summarize:
1) Departure Clearance (or any clearance): valid only if you remain in CAS and not altered.
True in the UK. Not true in Sweden. I don’t know for certain what the ICAO SARPs say. I’ll try to find out
2) D/R/P Airspaces: concern can be delegated to ATC in CAS and to pilot OCAS.
Well, “can be”… I would say the concern is the responsibility of ATC in CAS and of the pilot OCAS (for IFR).
6) OCAS: you can deviate from the FP without ATC permission like VFR flying. FP OCAS is more of a ‘notification’ than a ‘control’ value.
Without permission, yes, but not necessarily without notifying FIS. SERA leaves this to the national authorities to decide. Unfortunately.
Airborne Again, very useful clarification. I think I am now better informed, thanks to all for taking the time.
DMEarc
There are lots of IFR airports without both SIDs and STARs which are inside CAS.
Not if MAX DCT = 0
To connect to an airport without a SID or a STAR, you have to use a DCT, which is not possible if MAX DCT = 0.
Actually I believe the first statement is correct.
And you can file directs even if MAX DCT=0 provided you file to one of the waypoints listed as DEP or ARR connecting points for that airport as published in RAD Appendix 5. If the destination does not have STAR you just file to one of the ARR connecting points. If the departure does not have a SID, you file one of the associated DEP connecting points as your first en-route waypoint.
LFPT (my home airport) has STARs but no SIDs (except from POGO which are standardised routes between airports in the Paris area). If you look up LFPT in the DEP tab of RAD Appendix 5, you will find a number of intersections you can file as the first en-route waypoint. To depart from LFPT I have to file DCT to one of the DEP connecting points appropriate for my altitude and equipment, and I will receive radar vectors to that waypoint.
Concerning the route from ELLX to LFJL I did find the following route using autorouter:
ELLX N0128F040 ASMOX1X ASMOX DCT DIK DIK2A LFJL
The two airports have SIDs/STARs. You do not need to include SID and STAR in the FPL.
This is what ICAO Annex 11 says:
3.7.4.4 When an aircraft intends to leave a control area for flight outside controlled airspace, and will subsequently re-enter the same or another control area, a clearance from point of departure to the aerodrome of first intended landing may be issued. Such clearance or revisions thereto shall apply only to those portions of the flight conducted within controlled airspace.
I think this makes it pretty clear that, by the international standard, if you get a clearance to your destination and a part of the flight is OCAS, then you do not need any additional clearances. Your original clearance is still valid when you reenter CAS.
