FNW - IIRC and surmising what little was made available about the crash, the crash occurred because a NOTAR fan blade torsion strap let go, this probably slowed the fan momentarily which shocked the NOTAR fan which caused the NOTAR drive shaft to shear just aft of the rotor brake. This meant the NOTAR system had failed (but he could still move the thruster, but there was nothing coming out of it). And again IIRC the broken drive shaft then smacked into the main fuel line for the No 2 engine which sheared it at the decking quick release self sealing couple - so he lost his No 2 engine as well.
I recall he carried out a slow speed/hover check at height and lost is and spiralled in to a crash.
Yes the Yaw Trim switch does allow pilot input to the VSCS - below 50 kts the aircraft yaws, above 50 kts it 'kicks' the ball. However I gave you a blind alley as it made no obvious change to the basic condition.
Some of my instruction must have been flawed - tut tut!! That is not what BJ said on the day!!
Regarding landing on hard or soft surfaces - IMCO go hard everytime and keep it hard if you can!! Soft has been proven to be asking for rollovers - the Hannover crash appears to have been caused when the aircraft unfortunately ran off the runway into the grass verge and rolled over. I believe the Knaus Explorer crash a few weeks earlier also rolled on grass.
Anyway - having just spent some time playing with a simulated right pedal jammed forward in-flight, I can confirm that the Yaw Trim had no impact on the problem. You must keep the IAS above 90 kts plus (if not more) to feel as if I had some control - and that was into a 36 kt wind!!
As regards trying to get it down - well thats another story
