Lots of sorrow... lots of questions. As a controller my immediate reaction was "how could it crash 5km (6m in one quote) from touchdown simply because of fog?" Mode C should have been visible to ATC and no controller is going to allow an a/c to descend to ground level without doing something. I therefore suspect a major control problem, but who knows - yet?
I do get very distressed at the media - BBC, papers, etc., implying that fog was a major cause. A/c land in thick fog day after day with no hassle.