Detailed analysis of the debris field, physical damage, and other factors in the alleged impact of a Boeing 757 on the Pentagon building on the morning of September 11, 2001 reveals an almost complete absence of debris expected from such an event. (Elliott 2003) The initial (pre-collapse) hole made by the alleged impact on the ground floor of Wedge One of the building is too small to admit an entire Boeing 757. In order to decide whether or not a Boeing 757 (or aircraft of comparable size) struck the Pentagon on the morning in question, a comprehensive review of all the debris and other physical evidence is hardly necessary. It turns out that a study of the wings alone suffices for the purpose.
Wings that should have been sheared off by the impact are entirely absent. There is also substantial evidence of debris from a much smaller jet-powered aircraft inside the building. We conclude with a high degree of certainty that no Boeing 757 struck the building. We also conclude with a substantial degree of certainty that a smaller, single-engined aircraft, roughly the size and shape of an F-16, did, in fact, strike the building.
Over the last two years, beginning with the investigations of Thierry Meyssan (Meyssan 2002) and continuing to the present time, there have been numerous claims that American Airlines Flight 77 did not strike the Pentagon building. (Citoyen 2003) (Desmoulins 2003) Although we have arrived at similar conclusions, we do so on the basis of a more focused analysis, one that relies not only on photographs, but on measurements, aerospace archives, and to engineering and physical analysis of the Boeing 757, as well as the structure of the Pentagon walls in the area of the impact.
The analysis is, for the most part, of the simplest type, such as any reasonably bright high school student might follow.
This approach has become necessary in the climate of suspicion that surrounds any attempt to question publicly the claims by major media outlets that Arab hijackers, with one Hani Hanjour in the pilot’s seat, brought the aircraft in precisely on target. It is certainly true that Mr. Hanjour failed flying tests, dropped out of flight school twice, and on one occasion, a mere three weeks before the September attacks, was denied permission to rent a Cessna because he showed an almost complete lack of knowledge of aircraft instrumentation to rental personnel (Nat. J. 2003). It does little good to point these facts out publicly, however, because they are only what we call “suspicious circumstances.”
In short, a devil’s advocate might claim that in the three weeks before his failed rental attempt and the morning of September 11, he somehow acquired the necessary expertise to carry out a high-speed turn and dive worthy of a military pilot. We will show that it makes no difference whether Hanjour was an expert pilot or not. There are direct physical contradictions between the claims of the Bush White House, as echoed by the major media, and the facts on the ground. These contradictions are outside the control of the media, Mr Hanjour, or the authors, for that matter.
The analysis presented here is based entirely on standard and/or official sources, such as the engineering report issued under the auspices of the American Society of Civil Engineers (ASCE), as directed by an army engineering officer as chair. (ASCE 2003) That particular document details the damage to support columns inside the building, as well as providing an accurate track for the incoming aircraft, as revealed by the penetration of a presumed engine core to the rear of the inner ring. It was not within the mandate of the inquiry to determine what aircraft struck the Pentagon, but rather to evaluate how well the building withstood the impact, fire, and subsequent collapse of a section of the building.
Our general approach to the analysis that follows is to assume, whenever a range of options presents itself, that the White House version of events on September 11 is the correct one. For example, in determining the alignment of the incoming Boeing 757 engines with the support columns of the Pentagon, we have arranged the aircraft so that the engines were most likely to miss the columns that remained standing after the impact, in spite of the fact that a) this particular alignment was rather unlikely and b) the engines would probably have taken out both columns, even with this alignment.
In the first section below, we list all the relevant dimensions for three types of aircraft, as well as the walls of the Pentagon building. In the second section, we bring these elements together in a relatively simple analysis that uses basic principles and methods of physics and engineering that leave little doubt about the conclusions reached here.
At the very end of this article, we construct a mini-scenario that is consistent with both eyewitness reports and the conclusions reached in the analysis.
Measurements and dimensions
Two types of numerical data appear below. Manufacturer’s data may be considered as accurate to within the last digit that appears in a dimension. For example, if the Boeing company gives the wingspan of the Boeing 757 as 127 feet, we assume that the measurement is accurate to the nearest 6 inches, that being the midway point between one length given in feet and the one next higher or lower. Measurements acquired from photographs use simple scaling to provide estimates of dimensions (measurements, in effect) that carry an inherent error that is comparable to error term as it applies to manufacturer’s data.
Although we shall work primarily in meters, the international units used by all scientists, we shall constantly provide equivalent dimensions in feet and, where relevant, inches.
The Boeing 757 used by American Airlines Flight 77 was the 757-223 model. The relevant dimensions follow. Dimensions with the word “derived” following them were obtained from engineering drawings and a straightforward scaling technique.
Relevant dimensions of Pentagon (Infoplease, 2003)
height of building: 23.6 m (77′ 3″)
inter-window distance: 3.1 m (10′ 2″) (derived)
inter-column distance: 3.1 m (10′ 2″) (derived)
Relevant dimensions of Boeing 757-200 (Flugzeugtriebwerke 2003)
wingspan: 38.1 m (125′)
center-to-centre: 16.3 m (49′ 11″) (derived)
outside span: 18.5 m (60′ 8″) (derived)
max. diameter of fuselage: 3.6 m (12′ 4″)
max. height of fuselage: 4.0 m (13′ 2″)
Relevant dimensions of McDonnell-Douglas F-16
wingspan: 32 ft. 10 in.
Length: 49 ft. 6 in.
Loaded Weight: 13,564 kg (29,896 lbs)
Relevant dimensions of Tomahawk Cruise Missile (Raytheon 2004)
length without booster: 18′ 3″
length with booster: 20′6″
Claims that a Boeing 757 struck the Pentagon are difficult to substantiate on the basis of available evidence, primarily a suite of photographs taken by various individuals present at the scene, not to mention images captured by security cameras in operation at the time of the crash. We have, however, made every effort to accommodate the Boeing 757 as the crash vehicle.
The most helpful document in this regard is the report entitled The Pentagon Building Performance Report, issued by the American Society of Civil Engineers. (ASCE 2003). A diagram in that document clearly shows several tiers of support columns on the ground floor of the building (Wedge One) in the area of the impact. Although many columns within the general area remained standing, others were completely taken out by the initial impact or bent to one side, either by the impact or subsequent collapse of the floors above the affected area.
The outermost tier of columns is located just inside the Pentagon wall, a nearly three-foot thick structure of brick, concrete and limestone facing. Between every pair of adjacent windows there is a column behind the wall. Since the inter-window distance is 3.1 m (10′ 2″), so is the intercolumn distance. This dimension was developed by direct measurement from clear photos of the building, using known distances such as the height of the pentagon and simple mathematical scaling. The error term is approximately 5 percent.