ERROR: 'Engine Parts From the Pentagon Crash Don't Match a 757'

Proponents of theories that no 757 crashed into the Pentagon have cited the alleged incompatibility of engine debris at the site with the types of engines in Boeing 757s. Two of the more common arguments are:

• Only one engine was found at the crash site, whereas a 757 has two engines.
• The diameter of the engine parts in the wreckage are only about half the diameter of a 757 engine.

The Missing Engine

The idea that only one engine was found in the wreckage is supported by photographs of engine parts published on government websites. One photograph shows a portion of a diffuser inside of a building, and another shows a high-pressure rotor amongst some wreckage just outside the Pentagon to the north of the impact zone. The absence of photographs of duplicate engine parts that would have indicated at least two engines is cited as evidence that the attack plane had only one engine.

That argument is a classic example of the fallacy of negative proof. The mere absence of proof of the existence of something does not prove its non-existence. The argument is even weaker when one considers the source of the images showing engine parts. Evidence of a cover-up in the handling of the 9/11/01 crime scenes is rampant. Unlike photographs of the Pentagon's facade taken by passers-by, photographs from inside the building were presumably released only at the discretion of insiders -- officials who might have an agenda decidedly at odds with a genuine investigation. There might be other engine parts that were not photographed, or other photographs that weren't released.

The Too-Small Engine Parts

The idea that the engine parts photographed at the crash site were too small to be from an engine found on a 757 is based on a failure to appreciate that different parts of a modern high-bypass turbofan engine differ dramatically in diameter. The fallacy is illustrated by a passage in one of the more popular articles purporting to prove that no 757 crashed into the Pentagon: The Missing Wings.

e x c e r p t

title: The Missing Wings

authors: A. K. Dewdney and G. W. Longspaugh

Only one engine was found inside the Pentagon. The two images below show two parts of the single engine found in the Pentagon. The left-hand image shows what appears to be part of the rotor element bearing the stubs of vanes. The right-hand image shows what appears to be the compressor (front) stage of the engine encased by its housing. This engine is barely a third the diameter of a large turbofan engine that powers the Boeing 757. Images of Engine Found in Pentagon Turbofan Engine used in Boeing 757 The engines used by the Boeing 757 are similar to the Pratt and Whitney engine shown below (PW 2003) and have the same dimensions, being nearly three meters in diameter, more than twice the diameter of the engine shown above.

site: physics911.org page: physics911.org/net/modules/news/article.php?storyid=3

Contrary to the article's implication, the high-pressure rotor in the upper right photograph is in fact the diameter of such parts from a 757 engine. The following cut-away view of a turbofan engine similar to the ones used on 757s shows how much the diameters of the various parts differ. The high-pressure compressor and turbine rotors are only about one-third the approximately 8-foot diameter of the fan.

page last modified: 2007-12-20