Dalek, I too, remember the dramatic slide presentation given by AVM Day. However, the argument over cloud cover was discredited by the questions from Lord Hooson. Copy of the exchange between Lord H and AVM Day is copied below:
294. But of course your hypothesis necessarily assumes that the cloud was not only over the Mull but was over the sea to some degree, does it not?
A. No. I do not know how far the cloud stretched out over the sea, and it is not part of my analysis—Sorry, I have tried to use fact. Where we have talked about hypothesis is where you have asked me questions. I do not know how far the cloud extended out to sea. There is quite good evidence—I think Mr Holbrook's evidence on that part is quite good in that he says he saw the sun glinting off the window. So I do not have any difficulty with the notion that out to sea there is broken cloud, et cetera, or maybe no cloud, bearing in mind this was a south, 170 wind, over the sea, and the forecast and all the Met conditions were forecasting that as it hit the rising ground that is where the cloud was going to form. It would have formed a little bit off the coast but I have no idea how far off.
295. So you do not know when they changed the way point whether they were in cloud or not?
A. I think that is not true. I do not know for sure whether they were in cloud or not, but they certainly did not have the kind of visibility that they needed to continue a flight over the Mull.
296. I follow that.
So, with absolutely no doubt whatsoever, AVM Day doesn't know whether ZD576 was in cloud or not.
Awkward.....
Regards,
Brian
"Justice has no expiry date" - John Cook