TCAS FAN
Was it not the case with the now defunct Sheffield City Airport that at least one operator pulled the plug due to the lack of radar, a number of airproxes in Class G airspace and the subsequent inability to come up with a risk assessment that provided adequate mitigation to bring the resultant risk down to an acceptable level?
I don't know the exact circumstances of Sheffield City but from what I recall you are probably correct. I would assume that the airproxes were not between their own traffic but involved itinerant aircraft ? In that respect I would think the risks were far higher at Sheffield than they will be at CAX because of the greater number of GA airfields in the general area and the funneling effect of the low based controlled airspace overhead and to the west and north. My impression is the Carlisle area is very quiet in terms of GA activity. As for military activity one can see the potential for issues, but I would have thought these were containable by appropriate procedures.
But of course radar could provide an additional level of safety, or at least reassurance, though at a cost. My assumption would be that if the cost were assessed to be justified then both CAA and Loganair would require it. An alternative could be the establishment of an RMZ though an Airspace Change Process application is apparently neither quick nor cheap.