Just did this on the Autorouter: EGKA-EGJB. As usual it gave me various routes which would have my license burnt due to D036 etc 
but this is a good one:
The funny thing is that FL100 is in Class G for a long way south of GWC. The base of CAS rises to FL105 there.
I’ve been aware of the “Eurocontrol suggest” feature ever since the earliest routing tools I was testing in 2008 (it’s had a very variable history, often producing useless routes, and often nothing at all) but not before seen it suggest an OCAS route, especially one with such an enterprising DCT.
Being OCAS, one is going to get “service dropped” shortly after GWC and then you are a VFR flight so will have to get a fresh IFR clearance from Jersey before reaching ORIST
If you don’t get it in time, you will need a 60 degree roll angle to avoid busting CAS or D036 in that very narrow “box canyon”
It seems to me that the distinction is between being in the “airways” system, versus outside it. Whether you are VFR or IFR, controlled or uncontrolled is less of the issue. That’s because it’s generally quite easy to get a fresh IFR clearance to enter controlled airspace such as when you approach Channel Islands Class D. But trying to get a pop-up clearance to cross the Class A airway (eg when flying northwest from Cherbourg or Deaville) is considerably harder (I had to descend into cloud last time when I was denied that).
What’s also much more difficult is re-entering airways Class A once you’ve been dropped, although it did happen fairly seamlessly to me when cruising up to Scotland once. The airway on the west coast, near Carlisle, varies in altitude depending on military activity/time of day/day of week etc, so you get told you are leaving controlled airspace, handed off to London Information, and then have to be re-cleared to re-enter a few miles further on.
You will of course be squawking 2000 now when outside controlled airspace. I had my first “Squawk Conspicuity” message from ATC last week in the UK, which is now used when leaving a local radar controller (Freecall to next station rather than actively passed over with Contact). In theory, that should make it a bit easier to gain those pop-up IFR clearances/transits than before.
Lastly, is the title correct? Surely it’s Autorouter proposing the route rather than Eurocontrol, which just confirms if it validates or not. For routes outside controlled airspace, I suspect that validation is more likely to be approved.
The route appears to be Eurocontrol generated. See the image at the top.
All the routing tools (I was a beta tester of most of them, all the way back) worked by attempting to generate a route, and if failing (or in addition to) they sent a request to Eurocontrol for their suggested route.
The suggested route was often unflyable, due to a totally silly routing, but it was always entirely at a single level which is not what you generally want on a long flight (e.g. EGKA-LDLO might be suggested at FL160, when actually you would prefer FL100 for most of it).
