View Full Version : Pentagon

2002-Mar-07, 01:07 PM
This is way, way off topic, but I post it here only because this board has an excellent pedigree for de-bunking conspiracy theories of all kinds.

Please delete if it's too left-field.


2002-Mar-07, 03:19 PM
Okay, I'll take a crack at it.

1. Why did the aircraft damage only the outer ring?

Simple: the difference in energy absorption properties deriving from masonry construction. The WTC had a stiff inner core and a thin "tube" of steel around its perimeter. The Pentagon, in contrast, has very thick outer masonry walls. When the planes struct the WTC, they penetrated largely unchecked until they reached the central core where they were stopped. Note that in the footage showing the "exit" explosion on the WTC towers, the conflaguration is offset; the material causing this is that which missed the central core.

The concentric design of the Pentagon means that very litte force applied to the outer ring will be transmitted to the inner rings. There is no structure to transmit the force. Therefore if the force of impact is absorbed by the outer ring, much less damage will be incurred by inner rings.

Imagine a group of people standing in line to buy tickets for a movie. Let's say you run as fast as you can and plow into the person at the back of the line. If the people are standing close together, the last person in line will bump into the person in front of him, who will in turn bump those farther up the line. The force of impact is thus transmitted to other people in the line. If they are standing far apart, only the person you actually hit will be displaced to absorb your impact. It may be fully absorbed before he reaches the person in front of him.

Conclusion: This question displays considerable ignorance regarding the engineering of structures and their response to impact.

2. How could a large aircraft strike only the bottom floor of the building?

To say that a B-767 is 15 yards high is very misleading. That's the height to the top of its vertical stabilizer while sitting on the ground on its landing gear. My airport (Salt Lake City, Utah) is only two stories tall, yet dwarfs the B-767s it services. Sure, the tails stick up above the roof, but the bulk of the aircraft's mass is located much farther down.

If we assume the terrorist pilot aimed for the ground floor so as to weaken the structure from beneath, then it is quite plausible to presume the initial damage was limited to the lower two floors.

Further, the lower part of the fuselage on a passenger airliner is designed to collapse under hard impact. This is a "crumple zone" designed to cushion the passengers during a crash landing. When a B-767 lands hard, your luggage saves your life. This feature also would have diminished the aircraft's vertical aspect as it struck the building.

Conclusion: This question misrepresents the size and shape of the aircraft, and displays ignorance of aircraft design and operation.

3. Where is the debris?

It's ludicrous to expect to see large pieces of aircraft debris in a photo of the outside of the building taken from about 200 yards away. I would expect most of the debris to be inside the building.

Further, the airframe will respond to impact against a massive, dense object (i.e., the Pentagon) by disintegrating. No matter where the pieces are, they will be too small to see in such a photo.

Conclusion: This question is based on a faulty expectation.

4. Why pour sand and gravel?

To create a roadway for heavy equipment. Turf is notoriously soft and does not provide adequate support for the heavy construction equipment needed to recover from the attack. Gravel distributes the weight over a broader area. The dump truck appears to be spreading pea gravel, not sand.

There is bound to be a lot of buried cables, pipelines, and other conduits under the Pentagon lawn. These would be damaged by heavy equipment not provided with such a roadway.

Conclusion: This question displays ignorance of construction methods and equipment, and basic principles of engineering.

5. Where are the wings and why did they cause no damage?

I do not agree that the wings did not cause damage.

Further, the photos in question were apparently taken some time after the attack. It is not reasonable to insist that the wings ought to be still there and still recognizable as wings in any case. Recall that airframes will disintegrate under these conditions.

Conclusion: This question suffers from subverted support; it merely asserts that the wings caused no damage.

6. Why couldn't the fire chief explain where the aircraft was?

The fire chief clearly stated that small portions of the aircraft were visible during firefighting efforts. This is consistent with the observation that airframes tend to disintegrate under hard impact. Fire fighters are generally not experts in aircraft crash dynamics, and so he properly deferred the question to those he believed might be better able to describe what happened to the airframe.

Conclusion: This question is a red herring, attempting to ascribe a motive to someone whose motives are adequately clear.

7. Where is the point of impact in these initial photos?

In both photos the lower floors of the building are obscured by spray from fire fighters' hoses. Further, the presence of sooting on the exterior walls does not necessarily guarantee that the impact point is in the frame.

Conclusion: This question attempts to argue from silence based on selectively presented evidence.

Needless to say, this follows the pattern of conspiracy theories. The theory is purely conjectural and based on the assumption that the author can simply intuitively assert what must be so, regardless of fact or expertise to the contrary. The author is quite obviously ignorant of the sciences necessary to understand what he sees, and in any case he selectively presents only evidence which is either ambiguous or can be "spun" to support his viewpoint.

The destruction of a portion of the Pentagon is perfectly consistent with the crash of a large airliner.

The Bad Astronomer
2002-Mar-07, 03:49 PM
This is off topic (though interesting), and I think Jay has answered it sufficiently. I'm locking the thread.

2002-Mar-07, 03:49 PM
A couple additional points I'll make:

The aircraft did, in fact, damage the next ring (in fact, I think the crash damaged the outer three rings). You can actually see that the second ring is damaged in that photograph, but the upper level did not collapse so it's still up there.

Also, the site claims that the AP initially reported a "truck bomb" had damaged the Pentagon. I had my radio on after the WTC attacks, and never heard anything but an airplane blamed for the Pentagon.

However, I do recall an initial report of a car bomb at a federal building in Washington - did the person who put up this site confuse this report with the Pentagon? At any rate, why doesn't he link to any supporting documentation that would substantiate his claim of an initial report?

And, as with any "conspiracy theory," what's the point? He makes absolutely no suggestions as to why the gov't would make these supposedly false claims . . .


<font size=-1>[ This Message was edited by: SeanF on 2002-03-07 10:50 ]</font>