Could it be as simple as a C clip getting wedged up in the motor and restricting it's motor or stopping it all together? Where it causes the other motors to try to get the Phantom back to a normal flight that it (the Phantom) does not respond what our tx is telling it (the Phantom) what to do. I know for a fact that on a hard landing (Crash) my C clip has come off the bottom of my motor. The first time it did it the C clip wedged up in the engine so bad that I couldn't spin it (motor). I broke down Phantom pulled the motor apart and got the C clip off the inside of the propeller housing and went back flying with no problem. I got lucky so to speak. What I am trying to say is: 1) That C clip does not have to be on and you can have perfectly good fight or several. 2) You could do just the right move in flight and cause that C clip to go up into the engine and cause a parcel or full engine failure. 3) I think this is what causing some of the Fly-a-ways.