Original Message

I once flew an EC135 that would occasionally begin a slow roll oscillation that would increase in severtity. I have let it go on until it was alternating between left and right banks of 30 degrees. disengage the SCAS and it would immediately stop. No cautions, warnings or advisories. Maintenance coudln't figure it out. They just threw parts at it. One day they parked a spare next to it and switched out prettymuch every scas component and voila no more intermittent roll issue. However, a while later the spare began doing the same thing. Ive been wondering if this crew encountered the same kind of issue.