With regard to the real world, today, of EMS ops, Gomer's comments make a lot of sense. IFR ops alone are clearly not going to get the job done to get to accident scenes at night, so if you're going to have night EMS, visual flying is going to be essential - and will need to be practiced. Having said that if it was me doing it I'd want my IFR twin as well, to provide a safe(ish) exit in the event of loss of reference and to ease transits when appropriate!
But there are clearly huge extra costs in exclusively using IFR twins for night EMS ops. Are they justified? Looking at what appears to be the current profile of activity, probably not, on the assumption that the market talks.
But what facts are actually known in the US? What % of EMS night flights use singles? How many casualties are carried per year? In what % of those is the helicopter reckoned to significantly contribute to the saving of a life? What is the average cost per patient of EMS helicopter use, for both for singles and IFR twins? How many casualty lives are saved at what EMS crew life cost? What is the value of a life?
The statistics will go a long way to establishing what is reasonable in terms of singles or IFR twins for night EMS ops.
Anyone know any?