First, the background. I own an aircraft which is powered by a 912iS Sport engine, the propeller is a Woodcomp electrically controlled constant speed unit, the instrumentation is via Dynon Skyview HDX.
On Saturday I was flying when the instrumentation suddenly indicated information concerning Lane A voltage and fuel flow was missing - see attached picture. Worse, the propeller went full fine and the engine suddenly accelerated - I reacted and pulled the throttle back before it exceeded 6100rpm. At no time were any Lane faults showing, I cycled the Lanes to see if this would help (it didn't).
I switched the propeller controller into manual mode and was able to set the pitch and increase throttle back to a level to allow me to fly "normally" - with the exception of no Eco mode, so this showed that the controller was able to adjust the pitch of the propeller.
A few seconds after landing, the issue resolved itself - the information came back; I flew again 3 times and the problem didn't reappear but it was unnerving to have the engine suddenly go overspeed.
I checked the data from the Skyview - sure enough, the CAN data for the Lane A volts was missing when the issue appeared, as was the Fuel flow. But the RPM data was correct as were other data supplied via the CAN such as MAP, Oil Pressure, Oil temperature which I believe can rule out an issue with the CAN Bus..
As indicated, the Lane A voltage didn't drop to zero, it was just "missing", as if the system had switched off, before initialisation for engine start.
So my question: What can cause this data to go missing; worse, why would the lack of that data suddenly cause the propeller control unit command full fine pitch?
Any ideas?
