Absolutely structural problem. The wing was in great condition - never touched the ground or anything like that. I suppose that most of the airplanes (3D intended) will not survive the presure I was holding on it. So I guess Phoenix does not have to be blaimed on this. I have done a lot of other demanding aerobatics, and the plane was fine with it, so your friend does not have to worry about it. Just don't put full elevator and flapron on high rates when gaining speed in vertical descent.

Yaniv.