PT6A Np spikes. Experience?
Anybody come across random Np peaks in service? Prop running at approx. 2000rpm, but after a period in flight, the gauge just jumps up with no lever input.
All other engine indications fine and no prop hunting.
Lots of investigation gone on, mechanical and electrical, and installing a known serviceable but older Np tacho gene has apparently cleared it. Four new ones from the same batch all failed to shift the defect.
I don't need fault finding, just wondering if anyone else has seen this issue, and if so, would you be willing to share part details.
Cheers,