I was out flying in a park. I was wide open at about 25 feet after making one pass then a pretty tight turn. About 1 minute into my flight. I turned pretty hard right and pushed left stick forward to gain some altitude. Everything was fine to about 65 feet altitude. The maneuver was smooth. Then it just started tumbling and took a normal uncontrolled path down until it crashed. Display went into ATTI mode at the same time. I had calibrated it before and has 12 satellites I believe. I was full green, flying in P-GPS mode. I have had it go into ATTI mode at this park once before. That's why I've been calibrating every time I fly. The flight log showed it went in to ATTI mode four times over the final four seconds of the flight. It went ATTI to P GPS, back to ATTI to P GPS...you get the idea. I'm baffled.