Thanks for all the replies...all the type of stuff I was looking for.
No need to go back to the books Ironcheffley, unless you want to that is.
The optical probe for ice detection was mentioned for the S92. What do types such as the AW139, S76 and the good ol' S61 use for ice detection?
I'm afraid I'm from the little brother brigade, where the uncommon event of ice detection is on the door hinges and the windscreen wipers. Oh yea....there was also that calibrated bar thing that stuck out the side of a Lynx.