Hi CRAB,
I was being a little coy. Surely you know enogh about me now to believe I understand the rules well.
Essentially SPIFR requires ATT plus Height and Heading hold.
However SPVFR at night or over the water does not.
There is a strong safety case to say VMC night and overwater flight, both being navigated without reference to visual landmarks, an ATT plus holds is a must. However EU-OPS does not mandate this requirement.
Hence when we consider, in order of importance:
1. SAFETY
2. COMPLIANCE
3. COMMERCIALLY EXPEDIANCE
Flying overwater in a SAS mode machine meets 2 and 3 above. I want to be convinced that it also meets 1 above and with no personal flight experience of the EC135, our ship of choice, hence my rotorheads enquiry on this thread.
Hope this makes more sense now.