Hello Outwest,
interesting regarding harmonics @ 102% Nr causing problems with RB actuators. I will see if I can get any feedback from my sources in AW.
Something to consider in the meantime-I have long seen...and still see problems from RB actuators. Each time I begin to deal with the problem there is always some simple checks I do 1st:
-electrical cannon plug connected to RB actuator has a regular problem with the backshell coming loose causing intermittent CAS messages...always check to see if backshell is tight.
-RB caliper bumper stop shimming...you may remember that when the AW139 1st came out that there was no rubber bumper under the caliper. It was introduced originally as a BT if not mistaken. Anyway, in the instructions there is a MIN and MAX dimension/height of rubber bumper as part of shimming. I always go for the MIN height. Quite often I have found that the RB actuators giving grief that the bumper stop is at the MAX side of bumper height tolerance. With CB's pulled in IGN and START, I operate the Engine Mode Select switch between IDLE and OFF and listen to the sound of the RB actuator moving through its travel. As the caliper swings down and rests on rubber bumper the RB actuator is still trying move to end of travel until it trips its internal microswitches...but it is having to push against the rubber bumper to do so-excessive load on RB actuator. You can actually hear the sound of the actuator change as this happens. Going for the MIN height on rubber bumper shimming has always given me great results
-Location of caliper bumper stop...after completing the shimming procedure it is as important to make sure that the caliper bumper assy is centrally aligned to the hole in caliper assy. The caliper bumper assy has 4 elongated holes at baseplate for this very reason. Failure to check this will also have the RB caliper arrive at the bumper stop slightly early and cause excessive load to the RB actuator as it tries to move through full travel.
-RB caliper assy pivot shaft...over time has a tendancy to bind-in particular in hot environs, causing excessive friction and therefore excessive load when RB actuator is trying to move. I have recommended many times to include a proactive maintenance step of introducing a regrease of RB caliper pivot shaft at 600hr intervals as 1 suggestion.
Just my 2 cents worth.
Hope it helps