Abstract This article looks at The Pentagon Building Performance Report (January 2003) by the American Society of Civil Engineers (available on the internet). The key conclusion reached is that the Report fails in its attempt to show that the structural damage caused to the Pentagon on Sept. 11, 2001 was caused by a crash by a Boeing 757 aircraft. The main purpose of the Report seems therefore to be to back the official, untruthful story about the events of 9/11. However, part of the inconsistencies are so glaring that an intention of sabotaging the said main purpose cannot be excluded. The key conclusion is based on nine observations which can be divided into two categories based on whether they concern events prior to or during the crash of the aircraft. As regards the first group, the overall conclusion is that the approach of the aircraft and its being damaged cannot have taken place in the the manner put forward in the Report. This conclusion is supported by the following observations:
For the second group, the overall conclusion is that the Report's description of the impact of the plane and of the damage caused manifestly contradicts photographic evidence from the scene. The description includes impossible, contradictory and unexplained phenomena:
The uncertainties related to the alleged point of impact as well as the approach angle, vertical position and inclination of the aircraft do not weaken the conclusion presented herein that the Pentagon could not have been hit by a Boeing 757 in the manner described in the report. This is because changing one of these factors to allow the better explanation of a particular damage (or the lack of it) renders the other damage even less comprehensible. NB. This author is aware of theories promoted to suggest that the Pentagon was indeed hit by a Boeing 757 which was destroyed before it (or all of it) hit the building. While this possibility cannot be excluded offhand - and the conclusions about the impossibility of a B-757's crash reached in this article may not be directly applicable to such a case - no substantial evidence has so far been produced to back up such a theory. See also: Comments and
Questions on Jim Hoffman's Article Critical Response Received on the Pentagon Articles - and Responses 1. Introduction"The volume of information concerning the aircraft crash into the Pentagon on September 11 is rather limited." (p. 12)
The Report, published in January 2003, is a puzzling reading experience. It contains side by side detailed accounts on harmless topics (such as the damage caused to dozens of individual columns and beams or the laboratory fire tests of columns) and passing over with very few words things that are of key importance for the credibility of the official story. These include, first and foremost, the lack of facade damage where there inevitably should have been damage. Moreover, there are so obvious errors and contradictions in the Report that it is hard to regard them as unintentional. Therefore, it must be considered one alternative that among the authors or redactors of the report there have been persons whose goal has been to help refute the official story. Yet this attempt is desperate, for professionals and the mainstream media alike do not seem to have taken the Report into a critical examination. The starting point in the examination that follows has, nonetheless, been to assume that the information provided by the Report is correct in the absence of a specific evidence to the contrary. 2. The Chronology of the Crash According to the ASCE Report – Plus the Necessary Corrections2.1. Approach of the Aircraft2.1.1 –0.42 seconds: Why does the report provide a false approach angle?
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This picture shows the
moment of impact as reconstructed from the data
provided by the Report: a B-757 is hitting column
line 14 (circled numbers) at the angle of 42º.
The figure shows that both the fuselage and the
right engine should have penetrated the fence.
Yet there is only one hole in it, which makes it
obvious that either the angle or the point of
impact is markedly incorrect.
In order to establish the correct
angle the fence deserves a closer look. The figure to the
right shows that only one hole was created. The ones
below allow the determination of the location (~6 to 7 ft
from the corner) and the size (~9 to 10 ft) of the hole.
(Sources: 
In
the picture on the right the B-757's location and
approach angle are the same as in the Report's
picture seen 
This photograph shows that
the aircraft could not have approach directly
along the 31º trajectory, for lamppost B should
have been downed (A and B are also marked in the
picture above showing the 42º and 31º
trajectories).
This picture has been taken
on the bridge visible in the previous picture and
shows what most probably is the lamppost that was
downed first.
 But could it be that hitting the generator
separated the wing from the fuselage and turned
it so that its projection in the direction of the
wall narrowed down to 21 to 26 ft? [3] The most serious problem
of this fully fantastic scenario is that the wing
would have had to break at an unlogical point,
clearly beyond the engine even though the point
of the engine would be the most natural one given
the backward impact experienced by the engine
upon hitting the generator.There are different alternative theories as regards the fate of any portions of the wings that did not penetrate the building; see e.g. Dewdney and Longspaugh. |
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| Conclusion 2: The Report is able to present no rational support for its claim that the right engine's hitting a generator might explain why the outermost part of the right wing never hit the wall of the Pentagon. | |
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The
short answer is: in no way. The spools are not
not so much as mentioned despite the fact that
they are conspicuous in numerous photographs
taken at the site, including this one from the
Report (to which numbers of the spools have been
added). With the help of this picture it is
possible to see that the largest spools were 6 to
7 ft tall, for even though they are in the
background of the firemen, the largest ones are
nearly as high in pixels.
 In this figure the aircraft
is tilted to the same angle as in the Report (see
the small inset, ca. 8 º), and it is in the
stated height (the top of the fuselage at about
20 ft above ground). The height of the
second-floor slab is also indicated. The
following observations may be made as regards the
spools:
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| Uncertainties
are naturally involved in an analysis like this:
the height of the spools or the "real"
tilt or height of the aircraft. On the other
hand, the space under the aircraft can be seen
very precisely from documents downloadable from
the Boeing
website.
As regards the only possible approach angle of
31º, spool #4 becomes critical (the one closest
to the building, see the figure). However, photographs
clearly show that its height is not far from that
of the firemen. Furthermore, the place of spool
#4 was directly in the way of the fuselage. Of course, the aircraft's estimated height, based on the images of the security camera, cannot be considered exact. In another place the Report says the tail of the aircraft extended to about 45 ft above ground in which case the aircraft was roughly two feet higher than in the diagram - but no less than four feet higher than in the Reports picture seen above as the inset. At this greater height, the aircraft might have barely escaped hitting even the largest spool. The difficulty with this is that it would then be necessary to believe that a jetliner passed within a few inches of the spool without causing enough turbulence to overturn it. In addition, raising the aircraft has negative consequences on other parts of the official story, namely for the sliding of almost the whole aircraft into the first floor and for the already enormously difficult task of explaining the facade damage to the right of the impact point. These are addressed below. The height of the Pentagon is a question of its own. This measure must be correct if any conclusions related to vertical parameters of the crash are to be correct. Nearly all Internet sources (including the Pentagon itself) state that the height of the building is 77 ft 3½ in. Some say 71 ft or little more (like greatbuildings.com). The correct height of the facade is, however, most probably 66 ft as in the above diagram. [4] |
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| Conclusion 3: The cable spools show that the builing could not have been hit by an aircraft with dimensions similar to those of a Boeing 757 at a vertical position indicated by the Report. | |
2.1.4 –0.02 seconds: The
left engine's allegedly hitting a vent structure cannot
account for the narrow facade damage
As can be seen from the quotation above, the eyewitnesses cited in the Report say the left engine hit a ground-level vent structure just before the nose of the aircraft hit the building. Also the height and tilt information given in the report imply that the left engine should have hit the ground. It can be measured from the impact diagram that this vent structure must have been some 50 to 70 ft from the fence and ca. 52 to 85 ft from the building between the extensions of column lines 14 and 17. In other words, it must have been somwhere in the area visible in the firefighters picture below. The problem is that no marks left by such an impact can be seen. They may in vain be sought e.g. from the Report's figure showing the cable spools. The picture below is cropped to show the area to the left of the spools (the whole photograph can be seen e.g. here). The height diagram above shows that the 8º tilt shown in the Report's pictures is not possible given the vertical position of the aircraft, because the left engine would plough through the ground. Assuming a greater distance from the ground or reducing the tilt would, however, undermine these claims the Report makes about the actual impact: the right wing hit the building partly above and partly below the second floor slab and the left wing only below it, and the fuselage slipped under the slab into the first floor. After the following, final pre-impact conclusion it is time to turn to the impact itself.. |
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| In addition to the eyewitnesses, there is no material evidence that the left engine, or any other part of the left wing, hit anything else before hitting the building. Therefore, no natural cause can be presented for the sudden shortening of the left wing. The facade damage to the left of the impact point will be returned to below. |  |
| Conclusion 4: No support is forthcoming for the claim in the Report that the left engine hit something prior to making contact with the facade. Also no justification is given in the Report for the allegation that such a hit could even in principle explain why the outermost part of the left wing never hit the building. | |
2.2. The Crash
2.2.1 0.00+ seconds: What makes the fuselage slide through the 2nd floor slab into the 1st floor?
| The figure on the right is a schematic presentation of the impact of a B-757 into the Pentagon wall. The top of the fuselage is 20 ft from the ground. The report states as follows (p. 28): |  |
"With the possible exception of the immediate vicinity of the fuselage’s entry point at column line 14, essentially all interior impact damage was inflicted in the first story: The aircraft seems for the most part to have slipped between the first-floor slab on grade and the second floor."
How is it possible that the fuselage ended up mainly in the first floor? Common sense tells that he strength of a floor slab (steel-reinforced concrete) in its own plan is far greater that that of the nose of an aircraft - especially after the latter has just hit a limestone-brick-concrete wall. Furthermore, when it is taken into account that according to the Report the nose hit the outermost steel-reinforced concrete column of line 18, nothing could have been left of the tapering shape of the nose to cause the alleged sliding into the first floor. This is stated in the Report as well: "the front of the aircraft disintegrated essentially upon impact", p. 40. [5] An immense force would have been needed to deflect the aircaft to the first floor. The redirection would have had to take place within a fraction of a second; there was no damage to the second-floor slab further than about 40 ft into the building except for a deflection upward at 70 to 110 ft from the outer wall (Figure 6.5 on p. 38).
Iif it is assumed that the reason the aircraft did not hit the cable spools was that it was actually higher that suggested, even greater difficulties ensue for explaining why the damage concentrated almost exclusively in the first floor. Increasing the height of the aircraft with just a few feet would mean that the impact was mostly directed at the second floor. The aircraft had no vertical velocity but approached horizontally (p. 13).
| Conclusion 5: The Report's description of the interaction of the aircraft with the second-floor slab has no physical credibility. |
2.2.2 +0.06 seconds: A hit by the right engine and wing cannot in any way explain the facade damage right of the impact hole
 As the impact diagram shows, all facade damage to the right of column line 15 must be explainable by the hit by the right engine and wing and the tailplane. The engine should have hit the wall between column lines 16 and 17 and damage caused by the tailplane should be visible from the hole to the right side of column line 17 (which is more accurately seen in the impact diagram). The picture above was taken by Daryl Donley just a few minutes after the crash (source: Library of US Congress, cf. the Report's picture in the inset in the height diagram). The picture has been taken roughly along the aircraft's (31º) trajectory. As can be seen from the height diagram, accepting the Report's information of the aircraft's vertical position and tilt means that the right wing should have 1) made contact with the slab (whose height is ca. 14 ft from the ground) at the point of the engine and 2) been above the slab to the right of this point. The tailplane of the aircraft was clearly above the slab on the right side of the aircraft. However, no such damage can be observed in the (strongly lightened) picture above; one has to go all the way to the right side of column line 18 to find impact damage in the facade above the second-floor slab. Additionally, the yellow line drawn in the picture to mark the lower boundary of the facade damage at column lines 15 to 18 clearly falls to the right even though the Report says the aircraft was tilted to the left. Moreover, according to the Report, the exterior columns of lines 15 to 17 are loose at their lower ends while the upper ends are still attached to the second floor (p. 17). However, it seems that these hanging structures might have been severed from the 2nd floor slab. |
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What the Report calls "gashes" caused by "impact by the right wing" (p. 28) between column lines 18 and 20 has been marked with yellow rectangles (by this author) in the photographs below. Both pictures are in the Report. |
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When the wall is examined in photographs taken prior to the later collapse (above right), it can be seen that the second-floor wall left from column line 18 as well as the outermost column of that line seem to exhibit no impact damage. It is thus out of the question to assume that it was the slab which might have "severed the right wing approximately at the location of the right engine" (p. 35). As noted above, the right engine must have hit the building some 20 ft to the left of where the slab damage can be seen (i.e. between column lines 16 and 17). Whatever hit the wall between column lines 18 and 21 it was an object ca. 21 to 26 ft wide and it had already been severed before the impact. |
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| The
exterior column at line 18 is particularly
interesting. As has been shown above, the Report classifies it
as having "large deformation, with
significant impairment in function". With
the help of the Report's photographs on the
right, one can compare more closely the nature of
the damage to this column before and after the
collapse. Whatever was the cause of the damage,
it was not the crash. Has the purpose of the said classification been to ridicule the study, hoping that someone will notice? |
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| Conclusion 6: The impact damage to the facade on the right side of the entry point of the fuselage does not correspond to the size, shape and position of the alleged Boeing 757 presented in the Report. |
2.2.3 +0.10 seconds [6]: The facade damage to the left of the fuselage's entry point are inexplicable by a hit by the left wing
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2.2.4 +0.15 seconds: Why doesn't the tail of the aircraft leave any marks in the facade?
The problem of the official story
as regards the tail of the alleged B-757 is well
summarized in the Report itself (p. 36):
"The height of the damage to the facade of the building was much less than the height of the aircraft’s tail. At approximately 45 ft, the tail height was nearly as tall as the first four floors of the building. Obvious visible damage extended only over the lowest two floors, to approximately 25 ft above grade."
With the 8º tilt used above, the peak of the tail would have been 4-5 ft left from the midpoint of the fuselage; however, at the height of e.g. the third floor slab (which forms the top edge of the hole), clearly less than half of that. In any case, facade damage caused by the tail should be visible in the photograph on the right (source: U.S. Army Training and Doctrine Command, link no longer functional). There is none.
Additionally, there can be seen columns at column lines 13 and 14 on the second floor in the hole created in the facade. The third floor slab is about 26-27 ft from the ground. It is very difficult to understand why both the fuselage and the tail failed to damage it more than can be seen. And, as the top edge of the facade hole is straight and smooth it is out of the question that the third floor slab might have cut the tail off. The possibility of the tail having been damaged in any way seems also to be excluded by one of the eyewitnesses interviewed for the report, Mr. Don Mason: "As the plane entered the building, he recalled seeing the tail of the plane." (p. 13) This has major implications for the size of the aircraft that may have crashed into the building.
In the absence of any kind of natural explanation whatsoever, the lack of damage caused by the tail proves beyond any reasonable doubt that no aircraft of the size of B-757 hit the building.
| Conclusion 8: The absence of any kind of damage by the aircraft's tail excludes the possibility of a hit by a B-757. |
2.2.5 +0.81 seconds: Why does the Report evade the cause of the hole in the inner wall of Ring C?The Report in no way comments on what caused a large hole to be created in the inner wall of the Pentagon's middle Ring. The Report only says this:
In addition to this, the caption and a few pictures, there is not a word about the hole. Why would a Pentagon building performance report be silent on the cause of this "failure?" One could imagine the hole to be claimed caused by an engine, but as a matter of fact there is no mention in the report on what happened to the aircraft's engines inside the building. On the spot, it must of course have been visible what had emerged from the hole. Why are there no photographs depicting this (round) object? Why is the official story silent about the matter? A natural explanation is that the truth is not told because it cannot be told. |
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| Conclusion 9: The Report is not able to explain the hole in the inner wall of Ring C with the story of a crash of a Boeing 757. | |
Sensitivity testing
It is worth considering if and how uncertainties involved in the approach angle, point of impact as well as the vertical position and the tilt of the aircraft may have implications for the conclusions reached above. The table below contains those central problems of the official story which might in principle be alleviated by changes in the data mentioned. The entries in the table indicate how the data should be "corrected" in order to better accommodate the official story. It can be seen that the possible corrections are few and in part mutually exclusive.
| Point of impact | Approach angle | Vertical position | Tilt | |
| Intact cable spools | (Given the holes in the fence and the facade, these factors cannot be amended enough to have an effect.) | Higher | No tilt | |
| Slipping of the aircraft into the first floor | Hitting the facade between column lines? | (No effect.) | Lower | (No effect) |
| Slightness and discontinuity of facade damage right of the point of impact | (No effect with any reasonable amendment.) | Lower | Large tilt to the right | |
It should be noted that the lack any damage caused by the aircraft's tail remains fully inexplicable regardless of any meaningful changes in the four variables.
Final Conclusion
The Pentagon Building Performance Report by the American Society of Civil Engineers fails in its attempt to show that the structural damage caused to the Pentagon on Sept. 11, 2001 was caused by a crash by a Boeing 757 aircraft. Belief in the official B-757 story implies belief in physically impossible and inexplicable phenomena. More generally, no proof of the return of Flight 77 to the Washington area has been presented. On the contrary, e.g. any security camera recordings that would really show what hit the Pentagon have not been made public. (In May 2006, two series of still photos from security cameras were released, but they contain no evidence of a Boeing 757. See www.flight77.info and www.judicialwatch.org/flight77.shtml.)
The most natural explanation for the numerous errors in the Report is that it is a part of the disinformation campaign by the US authorities - the purpose of which is to prevent the truth regarding 9/11 from being revealed and thus to protect the perpetrators of those atrocities.
Questions and comments are welcome to: sy-k{ät}kolumbus.fi
References
[1] See pages 3 and 24. The team leader, Technical Director, US Army Corps of Engineers, Dr. Paulk E. Mlakar, was in fact allowed to enter the site as early as Sept. 14, although the Report contains no account of his early observations. His special area of expertise is blast-resistant design. He was an investigator in the Murrah Federal Building Study (Oklahoma City) after the explosion for which Timothy McVeigh was executed. [Back]
[2] The examination of the approach angle would turn into sheer clownery if Probst's statement of the wingtip was taken seriously - unless, of course the wings object that hit the building were extremely short. Nevertheless, the Report says the three eyewitnesses - interviewed by Dr. Mlakar alone, three months after the events - "collectively provide a coherent and credible account of the events" (p. 12). (The third eyewitness was a Rich Fitzharris who did not see the crash but only the later collapse.) [Back]
| [3] The outer part of the wing
can only have bent forward as a result of the
collision of the engine with the generator. There
has been a sudden backward force applied to the
engine, and the deceleration of the inner part of
the wing has torn the outer part loose. This
event does not seem a realistic option, but it is
examined in order to give the Report every chance
of explaining what happened. [Back]
The total height of the building, or that of the facade, is nowhere explicitly mentioned in the Report. On page 36, it says, "At approximately 45 ft, the tail height was nearly as tall as the first four floors of the building." This would not be a meaningful expression if the height of the building was more than 71 ft, not to mention 77 ft. Photographs (such as the one on the right from the Pentagon site) in which a giant US flag has been mounted at the top of the facade provide one means to assess the height issue. The flag is a so called "Garrison Flag" whose size is 20 ft by 38 ft (see e.g. here). If the left edge of the flag (38 ft) is used as a yardstick and the effect of the picture having been taken from above the roof level is ignored, the resulting facade height is a little less than 65 ft. This is too low a figure, for at the lower part of the photograph one pixel stands for more inches than above.
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There is no good photograph
available showing the whole facade as well as the
surface of the ground from a sufficient distance
so that the distortion due to perspective is
minimized. However, by combining two photographs,
one taken probably from behind Route 27 (source
unfortunately lost) and Figure 5.9 from the
Report as shown on the left, the height question
can be settled with sufficient precision. The
heights of the floors are from the Report as
interpreted above (bottom to top: as 14 ft 1 in,
12 ft 5 in, 11 ft 4 in, 11 ft 4 in and 15 ft 4
in). The ca. two-foot discrepancy at the roof
becomes understandable if it is assumed that the
heights are distances of the floor slabs and that
each floor's "own" slab is its floor.
Thus the structures above the bottom surface of
the slab above the fifth floor
are not included in the Report's diagram. In any
case, the second-floor slab is at about 14 ft
above the ground. [5] This can further be illustrated as follows: If it was possible to hurl a steel-reinforced concrete slab at an immobile aircraft at a speed of 780 ft/s, would the slab not plane off the upper part of the fuselage? [Back]
[6] The post-impact time values must be considered merely approximate. They have been calculated using the deceleration of those parts of the aircraft which traveled the farthest inside the building, ca. 30g i.e., 966ft/s2. [Back]