The possibility of a chain of events - weakened composite structure plus unusual, or extreme, wake turbulence seems to be emerging (and yes, this is all speculation, before anyone flames me!)
There is an interesting training manual for pilots and ATC published by the New Zealand CAA available on the web. It includes a couple of impressive pictures of wake effect of a CX 747-200 landing at Kai Tak. I can't copy these here, so follow this link (you will need Acrobat Reader, go to
www.acrobat.com if your computer doesn't have this):
NZ CAA Wake Turbulence Manual
Edited to point out that I wouldn't bother with this link unless you have a broadband connection (and even then it's a big file).
[ 15 November 2001: Message edited by: J-Class ]