Our program in Southern California has always used Twin Engine Aircraft such as the Bell 412, Bell 222 (B and U models) as well as the MD902's and even a BK at one stage. The counties that we serve in SoCal, insist that the aircraft that are used for the transport of patients ,are twin Engine. The bases that are located in the coastal areas need to be IFR twin engine aircraft to service calls further in the interior as well as out to sea where IFR approaches are utilised.
Many large corporations are looking at replacing many of the twin engine aircraft accross the country with the smaller Single engine AStars or similar. Hopefully though, the local regulations will ensure that we continue to fly larger more spacious airframes in the future. Looking forward to the new Bell 429's.
At least in your area, this seems to validate a common assumption that--sans a regulatory mandate for the more costly helos--economics alone rule ship selection.
I wonder if a private program exists that is able to balance profitability with a voluntary utilization of the better ships mentioned in this thread.
Great posts everyone.