There are 2 improvements to the RBA's that I can remember. One is an improved switch inside the unit. Evidently it wasn't handling the vibration very well. The other mod escapes me at the moment. I had it in an email, but deleted it. All new RBA's are SUPPOSED to be of the improved type. Yeah, we'll see.
As an aside, we had an instance where it was actually the pressure switch on the RBCM on the forward roof that failed. This made the caliper stay away from the disc, as the Rotor Brake always thought the helicopter was flying. It is a pain in the
to change too!!!!!