The bomb theory seems pretty good. We've got witnesses on board talking about the bomb and heroes rushing the terrorist with the bomb. At least one of the heroes thought the bomb was a bluff.
There are two to three distinct debris fields which indicates the airplane starting shedding debris before impact. The cell caller locked in the bathroom that reported the explosion may have heard the bomb go off. If it was a small bomb it may have breached the fuselage enough to cause debris to hit the engine and knock the engine off the plane to explain why one engine was found away from the devastating primay crash site.
In the crash of United Flight 93 in Pennsylvania, the FBI has determined from the onsite investigation that no explosive was involved. Passengers on the flight said in cell phone calls that one man had what appeared to be a bomb strapped to him.
http://www.msnbc.com/news/633205.asp?0cb=-41824124
Another link dies - here's the original text.
Comment: I'm surprised by this, now how are they going to describe the debris field and the explosions heard by so many? No bomb? What does that leave them?
The black boxes were located at the main crash site. This indicates the tail of the plane was connected to the fuselage at impact. Black boxes are located in the tail of the aircraft. So we can deduce the plane did not break in half like Flight 800 did.http://www.howstuffworks.com/black-box4.htm
If the bomb theory eventually is the story that officially gets told, then I think it begs the following questions:
1)How in the hell did a bomb in a red box get on board??!! Did these guys just roll that baby through the carry on X-Ray machine and get a "thumbs up"?
2) What is different today in regards to carry on packages than on 9/11/01? Can we really expect that a bomb could not be carried on now?
3) Why did the FBI deny explosives were used? How did it know so quickly?
4) Was the explosion caught on the Cockpit Voice Recorder?
5) Where in the plane did the bomb go off?
6) How did the engine parts get where they are?