Megapirates 3.1.5.R2

[1Quadman]

So I was doing Autotune on my quad everything was going well until it got to the pitch part. All of a sudden it just took off straight up really high I still had some control but could not bring it down. Finally it came down kinda hard hit the ground then took off again. finally when it came down close to me I throw my shirt on it to stop it from flying. Why would it do this??. It did it once before when I was doing the first test flight. Help PLEASE

Thanks

[1Quadman]

I have a AIOP V2 no GPS just the board