Battery Disconnect???

I cant start a new post
my ph 3 std after a 5 min flight ,I pressed return to home ,It turned started on its way half way back it stopped became un balanced unstable and fell to the ground from 50 meters high any thoughts It was in my sight the whole time and no wind I am at a loss to why .Some minor damage several short flights have been done since so it still works 2 short flights where even done after the crash before any charging cheers Ross