JP,
Sorry but I am even more confused now, on one hand you tell us that
"of course no-one knows exactly what happened during that flight, just to give one example"
but then go on to say
"the one thing we do know (without any doubt whatever) is that at waypoint change the crew had already broken the airmanship rules governing flight either in VMC or in IMC"
If no-one knows exactly what happened during that flight how can anyone arrive at "at waypoint change the crew had already broken the airmanship rules"
Especially as no one alive actually knows what could be seen from the Chinook flight deck windows.