Hi gents, having seen it happen, there was a lot of "interference" flying around at that time so cannot definitively discount AAA fire, but I recall (and have it on CVR) that Max checked in on the radio and then, within a second, we both saw the ac go in. They were on the inside of the in-place turn we were doing, hence we both saw the profile of the jet pile in. If I had to put money on it, I'd say CFIT.