Originally Posted by
Harrynz
I would argue that if the pitch link failed, the blade would remain in flat pitch. The blades use trailing link control with counter weights to help move the blade off zero pitch.
The good blade would still be under the pilots control but the tail rotor disk would now only provide half or even less less of its anti-torque ability.
I believe can see the pitch link unconnected in few frames in the the final flyby video before they land. When coming in to land you can see the tail rotor below the gearbox has significant pitch. The blade is advancing towards the nose and pushing the tail right, nose left. This is being commanded by the pilot.
As they lose airspeed and the vertical fin stops working, the pilot realises they have insufficient ant-torque and tries to abort.
What ever else might be true, it is clear that the onset of yaw was caused by a change in the TR rotor speed, not a pre-existing lack of TR thrust. The blades are turning one way, then reverse direction (the actual direction is irrelevant as it will/.may be skewed by frames rate) which I would interpret that as a sudden loss of TR drive. This might be due to an external influence from a TR pitch issue causing an large imbalance that results in the TGB becoming disconnected, then detached. Assuming the observations of there being an issue at all with the TR pitch link are correct. Otherwise it may be as simple TR drive failure, for any of the many reasons they occur.