Thanks Bob. I had one that did have an unusual vibration and drove me nuts a few days. I kept flying it with the crew trying to figure it out. ( It would do an odd shufle on occasion) after a few days we isolated it. Seems one of the dog ears on the lift link was cracked. now that would have been a thrilling ride had it failed. I still don't have a clue what caused it to crack.
BT