Classic PPRUNE debate - mostly no facts and people talking 100% out of their arses.
Big pistons - I love the way that you have decided that the weather was not changing, and you do it in such a forceful manner. Pity you're talking rubbish - I departed from ORK about an hour or so before the accident this morning. On both arrival and departure the conditions were rapidly changing. The runway went from completely obscured at about 1000ft to completely visible and back again - all in a matter of seconds. We were given several visibility/RVR reports during the approach, in quick succession - ATC at Cork are very helpful and understand their environment.
The Cat II approach there is known for its idiosyncrasies given the undulating terrain. TBH I was wondering myself how long it would be before there'd be an accident.
Now we know.