The ASCE's Pentagon Building

Performance Report

Arrogant Deception Or an Attempt to Expose a Cover-up?

by Sami Yli-Karjanmaa

First published Sept. 05, 2004, last updated 12/12/15

from SamiYli-Karjanmaa Website





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:

  • the aircraft's reported 42º approach angle is not possible for a B-757; >>

  • the aircraft's right wing's hitting a generator cannot account for the narrowness and discontinuity of the damage to the facade as proposed by the Report; >>

  • the intact cable spools in the trajectory of the aircraft are incompatible with the information on the impact contained in the Report; >> and,

  • there is no evidence to support the claim of the left engine having hit a vent structure; such a hit would also not explain the narrowness of the damage to the facade. >>

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 allegation of the aircraft's fuselage sliding into the first floor has no physical credibility; >>

  • the facade damage on the right side of the opening in the outer wall does not have anything in common with the shape, size and position of the alleged B-757; >>

  • the facade damage on the left side of the opening are not suggestive of the proposed impact of a B-757; >>

  • the tail of the aircraft left no visible marks on the facade while the Report in no way explains this; and, >>

  • the Report fails to provide any kind of explanation for the hole in the wall of Ring C. >>

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.


1. Introduction

"The volume of information concerning the aircraft crash into the Pentagon on September 11 is rather limited." (p. 12)

With this apt remark the American Society of Civil Engineers (ASCE) starts the Pentagon Building Performance Report's chapter that reviews the crash information. The ASCE established a building performance study team right away on the afternoon of September 11, 2001. This hurry was superfluous, however, since the whole team was allowed to enter the site only on October 4, after the removal of all debris. The team performed its work after this and was able to examine the immediate post-impact situation only from photographs [1].

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 Corrections

2.1. Approach of the Aircraft

2.1.1 –0.42 seconds: Why does the report provide a false approach angle?

A good starting point for examining the approach angle of the aircraft is looking at the Report's figure to the right. It shows an approaching Boeing 757superimposed on a satellite picture. This author has added the trajectories of the aircraft's fuselage, engines and the wingtips as well as the scale. The aircraft is approaching the Pentagon approximately at the 42º angle (with the normal of the facade) maintained by the Report with a speed of 780 ft/s (856 km/h). The timing of the picture is ca. 0.42 seconds before impact.

Additionally, arrows showing the corner of the fence bordering the area reserved for the trailers and other equipment of the Pentagon renovation contractors has been added to the figure. The aircraft made a hole in this 6-7 ft high fence that was situated some 100 ft from the building. The inset suggests that if the approach angle and the impact point stated in the Report are correct, the fuselage and the right engine of the aircraft should both have hit the fence (this can be seen clearly from the next picture).

ASCE, p. 19

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 the angle or the point of impact is markedly incorrect.

Of course, the Report's assertion that the angle was 42º should not be dismissed lightly, for it seems to have a sound basis: "The direction of column distortion consistently formed an angle of approximately 42 degrees with the normal to the west exterior wall of the Pentagon." (p. 34) And there is indeed a third possible explanation: both the angle and the impact point may be correct if the building was hit by an object that made only one hole in the fence, such as a missile.

The hole created in the facade extended column line 9 to 18 according to the Report, actually 9 to 17. Additionally, clear facade damage apart from broken windows was visible only at column lines 19 to 20, and the facade of the 1st floor had lost its limestone panels from line 3 to line 8. - "Hole" must be understood here in a broad sense, for the outermost columns of lines 15 to 17 are still visible in photographs with their upper ends still attached to the second floor slab (Sources: column damage figure and the facade damage: ASCE p. 53; the aircraft: Boeing; satellite image (on 7 Sept. 01): Space Imaging.)

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: Steve Riskus, Geoff Metcalf, Pentagon.)

Holding on to both the 42º angle and the hole in the fence (made by the right engine) moves the point of impact to column line 10. The facade damage that should have been caused by the wings should then have extended from column line 1 to line 19. Therefore it is more natural to assume that rather the angle than the point of impact is incorrect.

When a B-757 is put in place using the fence hole and the impact point (see the figure on the right), it can be seen that the approach angle was ca. 31º instead of 42º. It must of course be taken into account that such small-scale pictures do not allow measurements to be made with the precision of one degree or foot. However, the difference in question lies multiply outside any error margins.

At this stage it is good to have a look at what these two approach angles imply further away from the building. It will be shown that, assuming the information in the Report is otherwise correct, the 42º angle is clearly impossible and the 31º angle means that aircraft must have turned in a way that is not easily reconcilable with its later tilt.

In the figure on the right the purple line and area show the aircraft's trajectory and the area it covered with the Report's 42º angle, and the green ones with the 31º angle compatible with the hole in the fence. In both directions there are obstacles that were left intact by the aircraft. On the 42º trajectory there are overhead signs on Route 27 about a 1000 ft (ca. 1.3 seconds) before impact.

There are also three intact lampposts between them and the building. On the 31º trajectory there is at least one lamppost that the aircraft should necessarily have downed (those near to the top of the photo are along a lower road, see lamppost no. 30 below).

Eric Bart has analyzed the downed lampposts of which there are five according to him (the damaged posts have been marked with yellow stars and red X's and the closest intact ones with white stars). Based on all this it can be concluded that a B-757 can only have been the cause for the downing of the lampposts if it narrowly escaped hitting the overhead signs and while gradually meeting the 31º trajectory by turning to the right as the blue arrows crudely indicate.

The main problem that remains is that the Report says the aircraft was at the moment of impact tilted to the left (ca. 8º) and not to the right. The change of tilt should have taken place within a little more than one second in a speed of 780 ft/s. In the figure, a B-757 is in the same place and approaching the Pentagon at the same angle as in the Report's figure above.

In the picture on the right the B-757's location and approach angle are the same as in the Report's picture seen above.

The photograph on the left has been taken rather closely along the 42º trajectory.

As the aircraft is supposed to be flying only a few feet from the ground, the idea of a 42º approach angle can simply be buried on the basis of the lampposts visible both in front of and behind the overhead signs.

Satellite image: Space Imaging

The source of the picture is lost, but similar pictures can be seen on the site of the Pentagon Renovation Project.

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.

Source: Bart

Conclusion 1: The angle of approach, 42º, proposed by the Report, is impossible for a Boeing 757 because of the locations of the single hole in the fence and the intact overhead signs and lampposts on the motorway. The only possible trajectory is difficult to reconcile with the Report's information on the tilt of the aircraft at the moment of impact.


2.1.2 –0.12 seconds: Why does the Report suggest the tip of the right wing is shattered when the engine hits a generator?

According to the eyewitnesses cited in the Report both engines of the aircraft hit something before the impact, and this is offered as an explanation for the explicitly stated fact that the outermost parts of the wings never made contact with the facade. The right engine is said to have hit a 750-kW generator, situated near the corner of the fenced-in area. An employee of the Pentagon renovation project, Mr. Frank Probst says the tip of the right wing cut through the generator. The other eyewitness, Mr. Don Mason, only says the wing hit the generator. [2]

As the pictures above [sources: ASCE Report (left); Geoff Metcalf (right)] and the impact diagrams (42º, 31º) show, the facade was not damaged in the place where the outermost part of the right wing should have hit. This is also clearly acknowledged in the Report. It is worth quoting precisely what the Report says about the only possible explanation it offers for this phenomenon (pp. 35-36):

"In any event, the evidence suggests that the tips of both wings did not make direct contact with the facade of the building and that portions of the wings might have been separated from the fuselage before the aircraft struck the building. This is consistent with the eyewitness statements that the right wing struck a large generator before the aircraft struck the building and that the left engine struck a ground-level, external vent structure.

It is possible that these impacts which occurred not more than 100 ft before the nose of the aircraft struck the building, may have damaged the wings and cause debris to strike the Pentagon facade and the heliport control building."

With the speed stated in the Report (780 ft/s, i.e. 856 km/h) the engine hit the generator ca. 0.08 seconds before the nose and ca. 0.16 seconds before the tip of the wing (should have) hit the building. As it will be shown below, of the ca. 37-foot long part of the wing lying outside the engine only a disconnected part can have hit the building; the damage is restricted between column lines 18 and 21 and spans an area some 21 to 26 ft wide.

The wing had to be totally disconnected from the fuselage and lose at least ca. 8 ft of its length (13 ft, if the Report's 42º approach angle were accepted) in 0.16 seconds. The figure on the right is from the Report; the dimensions of the B-757 are not quite the real ones. Note the marking of the outermost column of line 18 with blue color here as in the diagrams above; this issue will be returned to below.

The Report mentions no object that the tip of the right wing could have hit before making contact with the facade, and no picture taken on the sport seems to show such an object. Moreover, it must be noted that no object could have dematerialized or vaporized the wingtip upon impact. Instead, any obstacle should either change the direction of the (tip of the) wing or decelerate it greatly in order to prevent it from hitting the building. For comparison: fully stopping a body from the speed of the aircraft in 0.16 seconds would require a deceleration of almost 1500 m/s2. In other words, the force needed would have to be more than 150g, i.e. over 150 times the gravity of the body.

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.

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.


2.1.3 –0.05 seconds: How does the Report account for the intact cable spools in the trajectory of the aircraft?

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.

ASCE, p. 16

What was the exact location of the spools in relation to the aircraft's trajectory? The answer to this question is presented below. The analysis on which it is based can be found here. (Please also note my comments on Jim Hoffman's article (October 2004) in which he refers to my analysis of the locations of the spools.)

With the real approach angle (31º) the trajectory of the fuselage of the aircraft goes over three of the spools. Would the aircraft have inevitably hit one or more of the spools?

To answer the question, the vertical position and tilt of the aircraft as well as the shape of its underside need to be taken into account. The answer proves to be affirmative.

In this figure the aircraft is tilted to the same angle as in the Report (see the small inset, ca. 8º), 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:

  • There is definitely space only for the smallest spool underneath the fuselage. The largest spool size is too large to fit under the fuselage. The middle size would not seem to fit but this must be considered inconclusive.

  • The Report's picture (inset): the aircraft is more than two feet lower, i.e. the top of the fuselage at no more than 18 ft from the ground. At this height, not even the smallest spool would fit under the fuselage.

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 The correct height of the facade is, however, most probably 66 ft as in the above diagram. [4]

Conclusion 3: The cable spools show that the building 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 somewhere 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..

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 aircraft 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 able to be explained 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 tail plane 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, 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).

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.

These figures are on pages 16 and 28 of the Report.

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.

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?

Conclusion 6: The impact damage to the facade on the right side of the entry point of the fuselage has nothing to do with the size, shape and position of the alleged Boeing 757.


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

What was the situation on the left side of the point of impact? From the impact diagram it can be seen that the damage should have extended to column line 6 (with the Report's approach angle, to line 5). The photograph on the right, included in the report, shows that to the left of column line 8 the damage is restricted to broken windows and missing limestone panels. The brick surface seems undamaged (cf. also Figure 5.7 on p. 26). There is no particular reason to regard the damage as caused by the left wing, for the brick surface was exposed all the way to column line 3 as can be seen from the bottom picture below (source: Pentagon). The Report also states, as quoted above, that the the "tip" of the left wing did not make contact with the building.

ASCE Report, p. 16

Conclusion 7: The facade damage to the left of the entry point of the fuselage is not suggestive of an impact by a B-757.


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). 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 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:

"There was a hole in the east wall of Ring C, emerging into AE Drive, between column lines 5 and 7 in Wedge 2 (figure 5.16). The wall failure was approximately 310 ft from where the fuselage of the aircraft entered the west wall of the building."

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.

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


Intact cable spools

(Given the holes in the fence and the facade, these factors cannot be amended enough to have an effect.)


No tilt

Slipping of the aircraft into the first floor

Hitting the facade between column lines?

(No effect.)


(No effect)

Slightness and discontinuity of facade damage right of the point of impact

(No effect with any reasonable amendment.)


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. the security camera recordings that would show what hit the Pentagon have not been made public for undisclosed reasons. (A trial has been opened by an individual who wants the videos to be published after the Department of Justice admitted in March 2005 that such videos do still exist. See

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.







[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]

[4] Many of the Report's pictures are quite blurry. However, the diagram of the floor heights of the Pentagon (left, only the outermost ring shown here) is impossible to interpret in such a manner that it would support either of the overall heights presented above. If the heights are read, bottom to top as 14 ft 1 in (this is stated explicitly in the Report, p. 45), 12 ft 5 in, 11 ft 4 in, 11 ft 4 in and 15 ft 4 in, the result is 64 ft 6 in, which, however, is difficult to reconcile with photographs of the facade. Although the ratios of the heights of floors 2-4 match, the portion of the building above the fourth-floor windows seems too high.

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.

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. [Back]

[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]