Some comments on the post by dechelski (a dozen posts above):
1. Tail section repair. I cannot find an absolutely credible information where the repair took place in 2001-2002, but heard from Russian radio (while driving a car this morning) that it happened in Toulouse, on the manufacturer premises. If so, there is no reason to suspect Airbus for not doing the job properly. Again, would be very interested to know where the repair was really done.
2. IMHO, talking about the bomb onboard, you are right asking "why not to do it over Russia?" Indeed, might be a double win for the bastards that implanted it. But all those (Russian) charters are often late (or even delayed for many hours) and timer alone would not be reliable to detonate the explosive over a pre-defined place. And a combination of a timer with a mobile link that sets it up when the plane is already on the run-way seems to be a) too sophisticated for those guys and b) leaving more traces (in a mobile/radio network) than a primitive luggage-looking explosive put onboard by a single jihaddist. With regard to the latter, I would like to see the Egyptian police and secret services thoroughly looking through personal files of all the airport employees servicing this plane that night/morning and maybe already treating some of them "in a proper way" to dig out the truth.