I think you are coming at the problem from the wrong direction. A 'Public Service' Helicopter is one that is staffed by folk who are not Policemen but provide airborne support for them in certain roles that are not associated (directly) with crime. A valuable role is searching for missing persons and there are other roles that can be added that will assist the Fire Service (those that were associated with the London Fire Service Bk117 trial can attest to its potential), the medical services (taking the local AA out of service for long distance inter-hospital transfers denies that service to the local population).
The crews can have Community Service Officer status or even be Special Constables but the prime purpose is not to fight crime directly by getting involved in feeling collars but indirectly by making resources available on the ground that would otherwise be consumed in ground searches. Just look at the vast numbers of cops that used to be called in for such searches. Photography and some surveillance can also be undertaken along with overhead control and command roles during major incidents such as fires and floods etc.
Having been intimately involved with HEMS, Police Ops and SAR I know a little bit about the subject and having had a number of fruitful discussions with the management of the London Fire Service some years ago I have some understanding of their problems too.
A Public Service (Civil Defence) Helicopter Unit (PSHU) has a lot to offer so please don't discard the idea out of hand. As with the AA and the RNLI service it's not the idea that is the problem, its not the funding concept that is the problem - it's getting started that is the hurdle. Trying to initiate the service with any kind of government funding will not work because those who hold the purse strings (Police Forces, Fire Service, Local Government and Central Government) will not part with monies that are committed elsewhere and because the 'turf-war' element that characterises our public services prevents cross-service co-operation.
We solved the problem in the AA world by direct action. Stephen Bond personally agreed to give me a Bo105, suitably modified for HEMS, free of charge for 3 months and when we went to the local NHS and said you can have it free they were unable to resist and we got the go-ahead. The 3 months became 5, then 9 then 12 and then we were self funding and the knock-on effect around the country has to be seen to be believed. All based on actual performance and local public support.
We just need the opportunity to prove it can work and I am sure the model will catch on.
G.