Was flying my 800 size Hex with APM 2.6, which I have had for about 10 months and has always flown great. Today I was flying only about 100 yards out when it would no longer respond to any input. I was in Alt hold at the time and it drifted with the wind for a few seconds then went in to Fail Safe. I looked down at my Futaba 14SG screen to see that there was no signal being read by the telemetry. Other than being close in flying, that would be OK, except when I played back the video from the GoPro I could see some wild shake and high pitch noises right before it started drifting. I downloaded the log and the only thing I could see was there seemed to be a voltage issue about the time of the FailSafe. As it was landing, everything seemed normal and I flew it again close by and it was fine. I would appreciate some help in determining the cause. I am also including the log and video link. In the log, the problem is around the 4:40 minute mark. The video begins a few seconds before the error. Thanks Everyone..