Does the rotation of the helicopter clockwise around the mast affect the RRPM measurement? I'm thinking about 550 RPM (for an R44?) at 102% would need 5% reduction to hit 97%, that's about 25 rpm drop, or once every 2 secs.
That R44 was rotating pretty quick - could that explain the horn going off at some stages of the problem, due to a relative measurement change?
I've heard before that LTE in a Jetranger can be exacerbated by the fuel governor sensing a lower RPM and reducing the fuel flow, but this may be a myth!
BW