This is my first post ever, so please forgive me if I mess this up.
Today I launched my ZOHD plane in autotune mode. The plane flew out nicely for about 10 seconds, then spontaneously went into Flight Mode = 1 circ, and a couple of seconds later Flight mode = 11 RTL. (This flight mnode = 11 is what showed up on my FPV goggles. Never seen that before.
The model climbed with 100% power to the RTL altitude and circled at 100% power until the battery died. I had NO CONTROL. Nothing. Tried switching modes, turning transmitter off/on. everything I could do and there was simply nothing to do except head for cover and wait for the outcome which was not going to be pretty.
Once the battery died the model continued to descend in a circle, maintained its airspeed and made the best landing I’ve ever seen! Much better than I have ever done.
My shorts are in the laundry.
You mentioned a dataflash log… 
On the face of it, it sounds like a relatively simple case of losing RC to the vehicle due to range limitations. Next most likely a physical failure (wire shaking loose).
Did you do a range check before throwing off?
Peter
No range check. Thank you. I’ll check the wiring.
More puzzling is the crash yesterday.
Would you be good enough to look over the dataflash log on this one?
https://drive.google.com/open?id=1C3r6fMPS-29poz-AzdSkBeX7kokT_iNM
I took off with good GPS lock in autotune mode. Climb uneventful then at about a minute the plane became uncontrollable and crashed badly.
It has no compass. And is a v tail. And yes, it’s the same plane as the first post.
Any and all help you can give me would be greatly appreciated.