In my limited career as a TRE for a couple offshore operators, I tried to follow a simple set of rules for assessing the SOP/regulation adherance by propective captains:
1. Did he know the rule (SOP, etc)?
2. Did he know he broke it? And why?
3. Did he understand the consequences?
This long drawn out argument, that I have read with much interest, has highlighted the fact that it is impossible to write a regulation or SOP for every occassion. Hence, at some point, a pilot will need to use their judgement.
I would like to point out that not all over-water flights are in the North Sea, in a Sea King or a 225. Not all multi-engine a/c fly over water either. Even in that limited scope the environment can be much more unpredictable than most of the airline flying that so many seem to be aspiring to (airports don't move around for instance). Writing an SOP also must take into account who is going to be following it (skill, experience, language) as well as varying conditions.
I must admit that I have not been a pillar of SOP adherance over my flying career, but I have made it a point to know them intimately and to try very hard to research 'why' they were written the way they were, then to back them up with the Air Law and the RFM and anything else I could get my hands on.
They are a great tool for keeping both crew members (or more) on the same page and for getting a head start on solving a situation or problem. I also believe that when SOP's seem to be getting the way of the operation, rather than helping, we need to start asking pointed questions.
Bringing Cougar 491 up is a sore point with me. I see far too much armchair quarterbacking on Pprune by people who have either not been there, or fail to mentally put themselves there when they read the reports.
It isn't easy to make the decision to deliberately turn off the engine(s) or to write off a helicopter unless mentally well prepared for it in advance.