Pete
The operation was single crew and the pilots were trained for that
So what you are you trying to say here - the second pilot was trained as.... a passenger?. So his training was eating sandwiches and reading magazines? Don't tell me - the magazines were about airline safety...
... so there was no requirement for that second pilot to be there at all, so as for the accident being a breakdown in crm or lack of input from the guy in the rhs ... not relevant in this case
To shun the opportunity of acting as a two-man crew supports my concerns about the attitude of this outfit. Let me guess - there was no briefing (of the second pilot) prior to take-off and in the event of an emergency he had no defined role?
The whole thing about safety is if you blame the engine failure, or the poor performance of Cessna twins, or the pilot who just plain made a devastating mistake, you are missing the point. The point is for each adverse event, what can you do to neutralize the threat.