I didn’t read the thread so if this has been addressed, forgive me. And also I just blasted through this shooting from the hip based on what I know and will clarify anything I missed or anything that isn’t clear.
I spent almost 10 years of my life around commercial and corporate aircraft, fueling everything from a Cessna 150 to the Concorde, I’ve been a private pilot for over 11 years, and I can tell you that all arguments I have read and seen are made by those who simply do not understand anything about commercial aircraft outside of “you pay money, you get on em, you land in another town, and they sure are big.”
People assume that aircraft are these hulking, solid hunks of iron hurling through the sky. When in fact they are rather delicate pieces of machinery that are for all intensive purposes a big empty shell. Consistently people ask where the wings are? The wings are in a billion pieces around and in the Pentagon. And many of those pieces either burned up, melted, or were simply too small to be identifiable as part of the aircraft.
It is important that you understand that many parts on an aircraft are made from a magnesium alloys. Magnesium does burn and it burns hot. If you’ve ever wondered why they use foam on aircraft fires instead of water, now you know. Throw water on burning magnesium and see what happens. (Please stand way back first…actually, don’t try this at all)
I’ve watched a video about “the missing 757” and they spoke of the BTU’s that JP-8 generates. Well, I hate to tell them this but JP-8 is a military fuel and commercial aircraft in the US burn a grade called Jet-A. It nearly impossible to ignite, is extraordinarily oily, and weighs about 6.7 pounds per US gallon. When burning uncontrolled it has a tendency to evaporate a fair portion of the source due to the heat, and burns very black due to its oily properties.
The 757 carries anywhere from 14,500 to 15,500 pound of it in each wing depending on the fuel density which can vary from 6.55 to 6.9 pounds. That’s roughly 2,150 gallons in each wing, and the aircraft has a center tank in the fuselage which carries around 26,500 pounds of fuel. (4,000 gallons) Assuming the aircraft was topped off (around 8,000 gallons) you need to now figure out where that fuel went.
Again this is easy. If you’ve ever seen a fuel delivery being made at your local station, that tanker truck is probably carrying around 8,000 gallons. Now you have an idea of what 8,000 gallons of fuel looks like, compare that divided into 2/2000 gallon portions and 1/4000 gallon portion slamming into the side of the Pentagon @ 400+ mph. Review the animated gif captured by the security camera and your question is answered.
You can easily see the fluidity of the fireball in the first few frames, and by the amount of smoke that is generated very quickly, that the impact misted much of the fuel and it flash burned. The black marks all along the side of the building are more proof that Jet-A has been burning there.
I also submit the picture below which is a frame from the animated gif that the Pentagon security camera filmed, and you can clearly see the aircraft and the AA insignia on the vertical stabilizer.
Some computer generated models that show what happened to the plane can be found in the links below. There are some really good renders that show where the wings went, and why the aircraft came apart as it did.
http://news.uns.purdue.edu/UNS/html4ever/020910.Sozen.Pentagon.html
http://www.cs.purdue.edu/homes/cmh/simulation/
http://www.cs.purdue.edu/homes/cmh/simulation/phase1/
http://www.cs.purdue.edu/cgvlab/projects/popescu/pentagonVis.htm