I'm at the other end of the flying spectrum, (airliners), and have no knowledge of the sort of flying here, so could someone explain the probable sequence of events?
It looks to me that once over the ridge, he yawed or turned left and then hit a tree. So, why do we think he turned left and why did he descend - was he hit by a downdraught? or rollers?
Comments about losing lift followed by increasing collective and then decaying Nr - would not the engine(s) spool-up to compensate for the extra load, or was the helicopter too close to the ground for this to happen in time? He seemed to be very close to the terrain.
Just curious about the physics of helicopters.