Plane's throttle cuts to zero when I switch from FBWA to Auto

ArduPlane Plane 4.0
1

I apologize if this is post is a duplicate of someone else’s, but I’ve been searching for hours and I have not found someone with a problem that directly relates to ours, just the same symptoms.

Our fixed wing plane flies fine in manual and fly by wire A and, when we’re using stabilize mode during a ground checklist, the elevons move in the appropriate directions. Despite this, while we’re flying towards a point on our flightplan and switch to auto, our throttle cuts to zero. Right now, I’m looking at the logs and I see that my compass failed during all 6 test flights. I plan on testing that tomorrow by recalibrating it, but is there any other potential fix?

Thank you.

Here’s one of the .bins for our flights. https://www.dropbox.com/s/qtvypk08w70j1w2/Flight6.bin?dl=0

2

Your TRIM_ARSPD_CM is 1800 which means 18m/s target airspeed during auto modes. You switch to auto at 27m/s speed. No surprise it cut throttle.
Set your TECS parameters and tune it. : https://ardupilot.org/plane/docs/tecs-total-energy-control-system-for-speed-height-tuning-guide.html