Have had the PV for about three weeks with only minor bad landings. Now with some confidence under my belt, I tried for an altitude "record" and pushed it to about 415 ft. Down range was about 2-300 ft. As I was bringing it down and closer in, I experienced a very violent right to left roll oscillation. I was still able to throttle down, and regained some control and continued descent. At about 50 feet up, the oscillations started again then it hit the ground. Fortunately, it was over a vacant lot, so only two props were damaged. Prior to this flight, I had switched over to NAZA mode and it seemed to respond to the Home Lock and Atti modes. I also calibrated the sticks before flight. All other gain settings are at default except for the gimbal, which is set to miss the stops. Pretty certain I was in Home Lock at the time of the crash. During the oscillations, I tried switching to fail safe, but got no response. After a minor check out and prop replacement, all seems fine, but can't be certain since the winds are kicking up and bouncing the PV around a bit. May have had some RF interference since I was in a residential area, but no overhead power lines around. The roll oscillations wouldn't seem to a symptom of compass issues. Very little surface winds at the time of the crash. Could this be an ESC issue? Any way to diagnose? Appreciate your comments.