I've been trying to practice smother flying for the past few weeks. When ever I think I'm getting better something odd happens or it seems I'm flying too rough. I thought it was me but last weekend my friends and I went out to fly and while experimenting with position hold and altitude hold the copter went a little crazy for a moment. I told them it wasn't me that had moved it so erratically and decided to land. We had been trying to monitor it using Mikrokopter tools and all looked ok. My friend who is a better pilot than me started to fly it and all seem ok when it decided to suddenly jerked around, start to clime then shot off to the left while he fought for control. It ultimately found its way into a very tall tree. With a friends good throwing arm, some line and a small weight we were able to shake the branch until the copter came crashing down, I uploaded the GPX files hoping someone could make sense of this. I have been frustrated fro months at not being a better pilot and now I think that the problem may have been something unseen with the copter. Comments and advice are encouraged and very welcomed.