1) Don't go flying when it's above 90 degrees (F) (a personal comfort issue, not a flight issue). 2) Always recalibrate compass after you swap batteries. 3) Make sure GPS has locked in to satellites. Actually, I don't know if #2 and/or #3 was really my problem. I didn't experience a "fly away" as such but the controls got very squirrely. Fortunately it wasn't too far away from me, maybe 150', so I could see how it was behaving and guess at the joy stick position it wanted to bring it back to me, if not for a rather hard landing. Breeze was about 3mph. I was flying with a new ARRIS gimbal, a ImmersonRC 600mw transmitter, in GPS mode, and home lock. The other possibility was the ARRIS interfering with the GPS (?).