Arduplane problem RTL,AUTO

Hello, I have setup my APM2.5.2 board to the Arduplane. I use a FPV Raptor 160. Stabilize works fine but when I switch to RTL the throttle goes off, the MissionPlanner say RTL. This also happens when I switch to auto. I have a 3D gps fix. I realy don’t know how to fix this issue.
Please help.

APM2.5.2-gps-3Dr radio

I did the RTL and Auto when the plane stood on the ground, could it be a safety that motor goes off when the plane isn’t in the air? I searched into the parameters but couldn’t find something about this.

I think in stabilize mode APM does not control the throttle. However in Auto and RTL it does. And yes I think you are correct as a safety feature it will not apply throttle if it senses it’s not moving. I actually had to put my plane in my van and drive down the street to verify this. I sure wish there was a way to test throttle position a better way.