Any sensible person knows the air ambulance should be based at BFS
It's not quite as 'obvious' as that. Basing in Belfast seems geographically logical but because of the skewed population distribution in NI it would actually amplify current disparities.
Fermanagh, Tyrone and Derry currently have the lowest patient survival rates because of distance and less-accessible routes ( as a result of lower population density and more rural distribution ). Therefore, basing an air ambulance at St Angelo would make sense since it reduces the outbound empty-leg time to the point of patient stabilisation and transfer.
For the eastern counties, conventional road-bound triage and stabilisation is much faster on-scene and the air ambulance would primarily be for the transfer process.