SASless, I accept the jibe, but he still did a great job, even if he was thinking of you when he did it!
Crab,
You must know that the TR servo is not at the TR but on the upper deck, and the force from the TR propellor moment is conveyed along the TR cables to the upper deck. The frequency of the cable tension response is set by cable tension, if the tension is very low, the natural frequency of the cable can tune down until it matches the natural frequency of the TR collective pitch and excite the "umbrella" mode of the rotor, sort of like collective bounce in a H-1. Since the TR stops are on the upper deck, the TR pitch can go to very big numbers, the ride is short, exciting and often leads to a TR failure. Cable tension is a nice thing. All this is speculation, of course, but I cannot explain the yaw twitches and obvious left yaw just prior to the TR failure any other way. I could be very wrong, it has happened before!!