I had the same thing happen to my Avistar. The wood bracing on the wing servo mount separated in the middle of the balsa wood and the servo was only hanging by the push rods. It was an easy fix, and I was very lucky that it happened on take off. I happened to take off very soon after I started and had plenty of runway left. The plane would only turn gradually to the right with no left at all. All I could do was pull back to idle and the plane made a sweeping turn and landed in our grassy area at our field. Just bent the landing gear a little. If I build a wing now with a single servo in the middle, I try to use basswood for the servo support so it doesn't happen again. Sounds like we were both lucky.