Ring Gear, when did the restrictions come in with T&B on the S-70, I was on them 88 till 92 and did the full range of adjustment, I had some smoooooth S-70 when I finished, was just looking at my old cheat book with all the T & B graphs ,1 x TR graph , 5 x MR graphs and 3 x graphs/charts to do cabin vibration absorber tuning, showed a young guy on Black Hawks all this stuff a couple of years ago and he said how did you do that if our computerised Vib gear is U/S we are grounded , I said old school old boys you had to know how stuff worked and work around it , something the "New Age" don't understand. Only ever used the concept of pretrack to do initials or to change a blade in the bush to fly you back to a maintenance place to T&B properly, I did the trials with RADS and 8500 in 89 and recommended RADS but the Army chose 8500 ???
I never had a Black Hawk die on me out bush/on a trip in 5 years , though what I did back then with U/S's wouldn't be allowed now.