TopBunk - Thanks for the info too.
I am only a humble SLF - and strangely enough after many years and many miles I have only ever experienced one GA. It was in I believe an AB320

dropping into Vienna one very very snowy night. It was a few years back and the FD door was open I had an aisle seat up front so watched us coming in through the snow.
There was no apparent reason for the last minute GA...it just happened. No explaition from the FD either.
IF I had known of PPrune back then I would have probably have posted something similar to Fintan out of curiosity in the hope that the wealth of experience possessed by the Piloting fraternity would enlighten a curious wingless person whether snow storms increase the risk of a GA......
The occasional naivity that comes through from us "un-enlightened" ones is usually treated with TopBunk's kind approach. If I wanted to get burnt to a frazzle I would try posting some comment in the MIL forum about how lucky the MIL chaps are to get all those free hours in their books before heading off to civy street. So please guys (piloty types with or without years of experience) keep up your NORMAL level of good will and kindness. Let the Mods Mod if they need to!