Regarding the other issues you raised :
1) AP turned off: I've also encountered this a number of times but with all off the chopper rather feels like balancing an elephant, still flyable, but nasty.
2) Trying to apply full rudder: I tried that, too. I don't want to say I applied it correctly or long enough, but, well, I tried ...
Have you ever watched Top Gun, where Goose dies because they enter a spin and don't manage to recover?
It felt exactly like that.
I am not saying that it really was a spin, or that it would be technically possible, I only state that no other reason of crash I encountered during my last half year of playing has even been close to being similar, which is why I initially started this thread.
I also really appreciate that you are trying to help me, but I feel a bit sad that most people suggest those every-day-reasons for this crash, whereas I tried to point out that I have had no evidence of such an ordinary occurrence, but in fact it really felt like a combination of vortex ring + spin.
Maybe (and it's not even unlikely) that one of you is right with their theories, it was late, I was tired and I have already been flying for a couple of hours before the time of crash.
However, I would really like to move the focus of this thread back from blade-smashing-trim-destroying-sams towards the question: "It there a chance that I did not err and might have encountered such a phenomenon as described above, or is it technically impossible that the Ka-50 (in this simulation?) can enter such a state?"
Thanks again