Could not a reverse step climb be used to seperate the aicraft by distance ie DME or GPS?
How much time maintaining FL190 on descent to facilitate separation with somebody held out at FL180 would be acceptable to you? We can only use DME/GPS when the aircraft have passed, not for any situation before they have passed.
the quickest and easiest way is for the outbound aircraft to climb out on a radial 10 degrees left or right
Well lets look at that. If you are tracking reference an NDB the tolerance is 6.9 degrees FOR EACH AIRCAFT, so 10 degrees will not work. 14 degrees won't work either, as we still need plazbot's 1 NM between the tolerances for lateral separation. The 0.2 degrees adds up to lateral separation at 294 NM from the aid.
If we take YLTN as an example this will look a bit sick with a rated coverage of 45 NM. You can't 'swap levels' on the aeroplanes the departure has left the lateral separation point, or you will need to finish it 5 minutes before the arrival enters it, and you will need to have achieved another form of separation before they leave the coverage, without introducing more complication. So departing aircraft needs to be turned 20 degrees minimum from what we expect the inbound aircraft's track to be, providing this doesn't cause a conflict with other traffic, otherwise CNARCCEAHAND. Inbound aircraft gets told to report receiving the NDB with track inbound. Until he does there is no clearance for the departure. Until the inbound is through a level the departure can climb to CNARCCEAHAND.
He departs and is told to report at 15 DME. Oh, YTLN hasn't got a DME, 15 GPS then. Oh, he hasn't got GPSRNAV, 5 minutes after we estimate he has passed 15 DME then. Hang on, that will put him around where he would be if we left them to pass in Class G airspace, then cleared the departure, and we took him off track as well...
Will he get above by 45 NM YLTN, if not what do you do? I read your post again, and note you are talking VOR, that makes it easier and you only have to turn the departure 16 degrees for the same effect, and the range is not such a problem, but no DME or GPSRNAV is still the same.
Without ATS surveillance or the flaky VFR procedures some pilots could not bring themselves to use the most efficient way to resolve these situations is that used by ATC in the USA. "Unable clearance, call again at [inconvenient time]". 'Cept we do it at FL180, them at 1200 FT AGL.
[CNARCCEAHAND - Clearance not available, remain clear class E airspace, have a nice day.]