I was thinking about this post today. I newer pilot at my field just bought an electric Katana, and was flying it at a school by his house. Fairly large area, considering it was a smaller electric plane. Well, he took off, made a few passes, and the plane started acting up on him. He brought it around to try to bring it in, the plane dipped, climbed, and took off on him, over the trees, flying beyond his sight and totally off over the trees. No one knows what happened to this plane, but he said he thought he heard it hit something, though he doesn't know what.

It happens.