I have seen, several of these plow in due to flutter issues. In all cases the builders had glued the servo mounts to the upper skin without any structural attachment to any of the wings frame. This resulted with flutter, servos falling out, and an eventual fireball. I'd attribute this to building mistakes, but also to bad instructions ( or total lack of ) . Look up my youtube channel, there are crash videos of a Rafale, and another of a Gripen that both go in the same way ( they have similar wing design as well ) ... sorry for your loss [:@]
http://www.youtube.com/wiwanczyk
~V~