Mission transfer failed;----param.4 has an invalid value--- "nan"

#1

New to Qgroundcontrol- I’ve made a simple mission for my wing-( fixed wing pixhawk with latest stable on both):
Maiden flight, so set up to calibrate airspeed (6 min loiter, waypoint 2) and trim (servo_auto_trim at waypoint 3)
–What parameter 4 are we looking at (see topic)?
“param. 4: nan” seems to be the problem. nan? Whazzat?

Another question about altitudes:
–What altitude should I use in “mission start” panel? Mission would logically start at ground level (0), would it not? But I suspect I’m wrong, because of the paragraph above that says the altitude becomes the default altitude for the mission.
In case it’s gps related, I’m working indoors, but with two GPS with around 10 sats and HDOP of 1.6 each.

#2

Are you using a Stable V3.5 version? I believe this may already been fixed.

#3

Which altitude in Mission Start are you talking about?