407 rotor smoothing with the RADS

[helofixer]

Found some shear bearings in the head of our 407 separating. Changed bearings. spent 2.5 days and 30 flights/ground runs to get the aircraft in track and balance. RADS gear constantly not seeing the blades, no matter what angle of the tracker , painting and repainting the blades. Night tracking is worse. Finally took all hub weight off, zeroed the tabs and set links to nominal setting and started from scratch. Took about 9 ground runs and 8 flights after that to get the ride close to spec and the crew ride to be ok. We have been using the RADS on our 206's and never really have problems. 407's is a nightmare every time, no matter which 407 we use it on (we own 2 and work on 2 other aircraft.) Anyone else have this much problem with the RADS? Do you use any other system? I know it takes time, and Ive been wrenching on 407's for 7 years and 206's for 14 years, but it seems half the time the corrections the box says to use do not produce results...ride gets worse and takes way too much time and effort to smooth the rotor. Any input?

[StirCrazie]

Mate I feel your pain, RADS can sometimes be a PITA. Why the tracker wasnt able to pick up the rotor is a confusing one, did it come up with the "tacho out of bounds" error, generally thats due to a light issue, either not enough or the suns directly in the trackers camera (but Im sure youre aware of this).
If you've been working on the 407's for 7 years you're undoubtably aware of hub shift issues and how sensitive the tabs are.
As for the RADS, I always print out the readings, view the predictions, use a little logic in accessing the corrections and edit the adjustables accordingly. I think the mentality of some people with "just follow the box" as little ignorant. Brake it down to basics, look at what the blades are doing, view the corrections. If it dont make sense ,dont do it, edit.
Sorry I dont have anything specific but I hope this helps.
Good luck

[helofixer]

We take great pains to fly the tracker out of the sun, but it doesn't explain why at night we have almost no success seeing the blades. We get errors of ABT apparently looking past the tips of the blades, and other errors or partial readings. We use a digital protractor to ensure the tracker angle is correct. Yes I am aware of hub shift, but do not suspect this at this time. Yes I am also aware that the trim tabs are very touchy, so much so that I have asked my boss for the trim tab gauge and bender with the dial indicator so we can at least try for those .2 degree of tab adjustments.

We had myself and our director of maintenance with a total of 35 years of helicopter maintenance stymied. I can run the rads on our L models and B models all day with no problem. 407, not so much.

I did get an interesting email from RADS tech support about people in the field reporting tracker errors on aircraft equipped with Garmin Avionics, especially the Garmin 430 and 530 GPS/Nav com radios. He stated that a Bell customer service rep reported problem after problem and tried 2 different sets of RADS and did not have any luck until they turned off the GARMIN radio. Pass this information along, it may save a mechanics' sanity. For sure next time I work on any of the 4 407's that all happen to have a Garmin, it will be powered down.

[StirCrazie]

Thanks for the tip, I'll be sure to try that one myself:ok: