Hi,
it crashes every time and directly after I sit in the cockpit. Loading screen still do work.
In the end I found out that it does not crash if I disable parallel projection.
I have no overclocking active.
But it may have someting to do with suddenly changed resolution settings in SteamVR. For some reasons the resolution settings change and if they are too high, the game crashes…
Now I I have tried it again with Parallel Projection an now it works.
So it seems that this topic is solved.
Thank you all for your help!