ERROR: 'Aircraft Crashes Always Leave Large Debris'
Photographs of the Pentagon attack site
show an absence of large intact debris
such as recognizable pieces of the tail or wings.
Since the areas of punctured walls in the facade
were not large enough to admit the outer halves of the wings
and the vertical stabilizer of a 757,
the absence of large pieces of these components
is cited as evidence that a 757 did not crash there.
The expectation that a jetliner crash at the Pentagon should have left
large debris is reasonable given the fact that other
jetliner crashes have left large pieces,
such as those shown in the photographs on this
from the talk
The Pentagon Attack Frame-Up.
However, several points should be noted here.
- The photographs in the talk are not necessarily
a representative sample of jetliner crashes.
- Even in those photographs,
it is remarkable that so few large pieces survive
other than the few intact pieces.
- The size of debris from a jetliner crash
is highly dependent on the nature of the crash.
Whereas a plane that skids and bounces on the ground
will likely survive in one or more large pieces,
one that flies directly into the ground will not.
The F-4 Crash Test
A 1992 report by Sugano et al describes an experiment
involving the crash of an F-4D Phangom jet fighter jet
into a 10-foot-thick concrete block at 480 mph.
In the experiment, the fighter is reduced to confetti,
leaving no large pieces of debris.
These images from the F-4 crash test,
are from the
Sandia National Laboratories Video Gallery.
The crash of an F-4 into a concrete block at 480 mph,
though different from
the crash of a Boeing 757 into the heavy masonry facade
of the Pentagon at a similar speed,
does suggest that the jetliner crash would also
leave no large pieces of debris.
Crash of C-130 Into Apartment Building Leaves Only Small Debris
Crashes of aircraft into buildings are rare,
so it is difficult to find crash photographs from which
to draw conclusions about the kind of debris such crashes typically leave.
However, a recent crash of a military transport plane is instructive.
On December 5, 2005, a C-130 --
a plane similar in size to a Boeing 757 --
crashed into an apartment building in Azari, Iran
while attempting to make an emergency landing at a nearby airport.
Photographs of the crash scene (see right margin)
show no large pieces of aircraft debris,
except perhaps a third of a wing and some engine cores.
If the absence of large visible debris on the Pentagon's lawn
from the crash of a 757 is surprising,
then the absence of large debris at the Azari crash scene
should be more surprising, because:
- The Pentagon crash punctured holes in the facade large enough to
admit into the building
the entire aircraft except the outermost wing and tail sections.
Photographs of the Azari crash show no punctures of similar size
in the apartment building.
- The Pentagon attack plane was flying at over 500 mph,
according to the ASCE's report.
That is much faster than the landing speed of any aircraft.
At its lower crash speed, there was much less energy to
break up the C-130.
page last modified: 2010-06-26