Time to put this one to bed as it reaches 100 replies.
Thank you to the experts who have put forward hypothesies which are palusible and goodbye to the 'experts' who obviously have no idea what they are on about but like the way they 'sound'.
One point reference the 'wake' comments heard on the CVR, I would suggest that perhaps the pilots 'thought' the vibration or shuddering he was feeling might be due to wake turbulence as a catastrophic structural failure is not likely to be the first thing that springs to mind.
For the uneducated in flying matters I would just like to point out that in ANY situation we pilots are taught to AVIATE, NAVIGATE and COMMUNICATE in that order and so those of us who fly for a living will have sympathy for the pilots during the horrendous events that overwhelmed them and of course for the rest of the crew, passengers and people on the ground and their families and friends.