Pentagon Impact Damage
Some skeptics of the official account of the Pentagon attack
have claimed that the pattern of damage to the Pentagon's facade
does not have much relationship to the profile of a 757-200,
the kind of plane that
Flight 77 was.
Often, such claims are based on erroneous descriptions of the impact damage,
such as making only a
in the building's facade.
e x c e r p t
In the simulation above, the damage to the facade was determined
by combining multiple photographs, each of which clearly
shows the condition of some portion of the wall.
The clean lawn shown in the simulation is misleading, since
none of the pre-collapse photographs give a clear picture of the
condition of the lawn near the building, and some show
significant debris fields.
It is also misleading in the following two ways:
- It makes objects in the construction yard
appear right up against the facade,
supporting the idea that objects in the flight-path remained standing.
In fact, the cable spools that appear against the wall
were 25-70 feet away from it.
- It depicts the plane as a stainless steel solid object,
reinforcing a common misconception about the construction of aircraft.
In fact, jetliners are very light and fragile compared to buildings,
their aluminum hulls being less than 2 mm thick.
Photographs show that the maximum extent of impact damage
consisting of broken-away walls is about 96 feet wide
on the first floor, 18 feet wide on the second floor,
and about 26 feet high.
This contrasts with an impact profile of a 757 at a 45-degree angle
to the wall of 177 feet wide and 40 feet tall.
There is a question of how much the impact of a 757
would have damaged the thick masonry walls of the building.
Perhaps the walls were strong enough to prevent breaching
by bulky parts of a jetliner such as the outer wings and tail.
The situation is somewhat analogous to a
involving the collision of an F-4 with a concrete block.
In the test, the entire plane was reduced to confetti,
while the concrete block sustained only a shallow impression.
However, examination of the Pentagon's facade reveals that regions that
would have been hit by the wings and tail of a 757
show neither broken windows nor evidence of scoring
of the relatively soft limestone.
Also, photographs show what appear to be still-standing columns
where some of the densest and longest parts of the plane would have passed,
such as on the first floor to the right of the hole's center,
where the right engine would have entered,
and an apparent dangling column in the second-floor puncture,
where the upper part of the fuselage would have entered.
However, it is not clear that those objects were columns,
and there is evidence that the
leaning objects on the first floor are not damaged columns,
but are hanging pieces of the second-story floor.
One deficiency of analyses purporting to show that a 757 impact
could not have produced the observed damage to the Pentagon
is a failure to take into account the blast hardening of the facade.
The nature of that hardening remains,
like all information about the structural composition of the
buildings attacked on 9/11/01,
the subject of considerable uncertainty.
For example, if the windows were composed of thick polycarbonate panes,
they may have been able to repel lighter fragments of the plane
Nonetheless, the apparently unscored limestone
in the predicted paths of the wing ends and tail section
are difficult for many observers to reconcile with such a crash.
One suggestion is that portions of the jetliner
were destroyed just before impact,
as proposed by French researcher
fragmenting these components into small debris
so as to leave no impression on the facade.
Meanwhile the punctured areas of the facade were large enough
to admit the vast majority of the aircraft into the building.
page last modified: 2011-07-04