Actually I have been looking forward to get any reply here.. Thank you so much for taking the time.
👍
We are suspecting the link connecting the dampers and the flex beam. On ground when v are flapping the blade there is a different noice coming.
As u described.
There is also a replaceable spherical bearing inside the Blade cuff on a beam that attaches the flex beam to the frequency adaptors. I would check that as well as it can turn into a maraca quite swiftly once it starts wearing, this will also affect the track and hence vertical balance. It is best practice to change all of them if you find one worn.
Thanks again.