.../... In that split second, my brain flooded with adrenaline and I watched
everything play out in ultra slow motion .../...
At the point where the fuselage hit the wall, it seemed to simply melt into the
building. I saw a smoke ring surround the fuselage as it made contact with the wall.
It appeared as a smoke ring that encircled the fuselage at the point of contact and
it seemed to be several feet thick. I later realized that it was probably the rubble
of churning bits of the plane and concrete. The churning smoke ring started at the
top of the fuselage and simultaneously wrapped down both the right and left sides of
the fuselage to the underside, where the coiling rings crossed over each other and
then coiled back up to the top. Then it started over again -- only this next time,
I also saw fire, glowing fire in the smoke ring. At that point, the wings disappeared
into the Pentagon. And then I saw an explosion and watched the tail of the plane slip
into the building.
It was as if he leveled out at the last minute and put it square into the building.
The wings came off as if it went through an arch way leaving a hole in the side of
the building it seems a little larger than the wide body of the aircraft. The
entry point was so clean that the roof (shown in news photo) fell in on the wreckage.
A lot of things have been written on this subject, including on the
previous versions of this web site. A geometrical analysis of the destructions
caused by the plane (lamp poles, damage before impact, damage on the front)
makes it necessary to plot sketches of the scene. This gives an engineer's view of the
situation which avoids to make mistakes and/or allows to get rid of some
hypotheses on what stroke the Pentagon on september 11 2001. The first diagram
shows the scene before the attack, with the items already listed upper on
a previous page. All the coordinates of items have been seized on a satellite
photo, then analytically transformed to coordinates in the diagram.
This reconstitution has been done on a scale double of the scale of the
images presented below, i.e. one pixel for 10 cm (3 pixels / foot).
The errors resulting of the overall process are around 0.3 m (1 ft),
with a maximum due to the fuzzy quality of the original image of 0.5 m
(1 ft 7").
The following diagram shows the arrival of a Boeing 737-200.
The plane is figured, at right scale, on the path where it is after having struck
the lamp poles. This axis is confirmed by the damage inside the building.
The purple central axis impacts building between pillars 13 and 14.
The two purple dotted lines correspond to the damage made to the wire netting fence
on starboard and ventilation structure low wall on port. They are supposed to be
the paths of the two engines. It is obvious on this diagram that the two engines
of a 737-200 are too close from the centerline to account for these damage.
The yellow line touching the building's front is the extension of the damage
on the building, from pillar 8 to pillar 20. Two dotted lines have been drawn
from it's extremities, parallel to the trajectory. It seems that, if the
port wing could be supposed to have damaged the front on this extension, the
starboard cannot. But this is not an evidence : admitting that the central axis
could be shifted a little, a 737 could be responsible of the damage seen on
the Pentagon's front. In a previous version of this web site, I even wrote
that the damage fitted exactly the size of a 737, and I was not very far from
the truth if considering that the plane kept it's structural integrity when
hitting the building. It allowed me to state the hypothese of the "junked
737" attacking plane. It is, indeed, reasonning at the limit, and excludes smaller
planes such as a commuter plane, a fighter like a F 16 or - still smaller -
a cruise missile.
Now the following diagram shows the arrival of a Boeing 757-200, which is
officially the hijacked plane of flight 77.
The plane is figured, at right scale, on the same path as for the 737.
The purple central axis and supposed paths of the two engines are the same.
It is obvious on this diagram that the two engines
of a 757-200 are just at the right spacing from the centerline to account for
the damage on the generator and on the ventilation structure.
The yellow lines are also the same as previously. It is clear that, if the
starboard wing can approximately be supposed to have damage the front on this
extension, the port wing should have damaged on a much wider zone.
In other words, a 757 is too large to be responsible of the damage seen on
the Pentagon's front if we assume that the plane didn't break into pieces before
hitting the building.
The starboard engine has damaged and moved the generator (not shown).
The nose impacts on the building. The port engine is destroying some of
the parts above ground of the ventilation structure.
A geometric construction is possible at this precise time assuming
the plane as a solid object. But from this time, the extreme deceleration
applyed to the plane's body implies that it must be
considered as a set of soft materials.
Witnesses account for the fact that "the wings went
forward" when the plane hit the front of the Pentagon. This is normal, on a
structural analysis. The deceleration applied to the body of the plane when
the nose hits the wall is tremendous. The wings are not build to support such
efforts and, pushed by their own inertia, "want" to keep their speed : containing
the landing gears, engines, fuel tanks, the wings are indeed heavy parts of a plane.
They must have taken their autonomy to bend forward along the body of the plane,
acting as whips. This "whip effect" had two consequences :
The roots of the wings stayed probably attached to the plane, at least because
the main structural beam, located approximately at the first third on the
wing depth, was deformed and not sheared. We can consider that the translation
energy of the wing was transformed into a movement of rotation around a pivot
which can be located approximately at the junction of the wing with the fuselage,
at the first third of wing's depth. If we "detach" graphically the wings from the
body of the plane, and plot on successive sketches what the movement could
have been, we get :
The body is shifted, the nose towards the port side, by the shock against
the front of the building.
The wings, taken forward by their inertia, fold along the axis of the body.
The port engine impacts the low cement blocks which had been put there to
protect the ventilation structure. The nose of the plane is depicted entering
the building, as if it was strong enough to pierce the external wall upon
impact. This is naturally false, the front of the plane acting much probably
as an accordeon in this phase. This graphical presentation doesn't show
it, just because I'm lazy when using graphics softwares and don't have sophisticated
tools to mix bitmap / vector graphics in the way I would like to...
The body is shifted a little more.
The wings keep on folding along the body.
The two engines are near to touch the belly of the plane.
The starboard wing is drawn according to the hypothesis that it broke against
the building. The wing tip has probably bounced against the building and, due to
this shock, did not fold as much as the port wing.
The process is going on.
The starboard wing is partly inside the building, partly outside.
Two effects must occur, not figured on the sketches :
The two engines are inside the belly of the plane.
They will join their masses to the plane's body to create
the important damage at the "entry hole" in the front of the building,
around pillar 14. The port wing tip has now taken a very important speed
(supersonic) by "whip" effect. It will go through the contractor's trailor
located on it's trajectory and explode it. The other trailor is destroyed
by the port engine and part of wing nearer from body. The wing tip is
going to raze pillar 8 (or even touch it a little) before entering
Both engines are inside the building. The port wing has hit the front and, due to
it's speed, destroyed the pillars and walls. The whole plane will now enter the
building through the holes done mostly by the two engines and the port wing.
It is possible that the tip of the starboard wing, having bounced on the building,
could collide with the tail of the plane, for example right on the vertical
This process is coherent, only under an hypothesis : the damage left at second floor
level by the tip of the starboard wing must be considered in the maximum extent.
According the the upper sketches, these damage should extend up to pillar
22. As a matter of fact, the impact point of the wing tip would be just
after this pillar.
The following interactive diagram summarizes the sketches shown above. Click to
show plane's progression.
On the front line of the building, on line "AA", equally spaced columns support the
building's front. The distance beetween them is approximately 3 m. On the impact zone,
on the first floor, the following damage were created to the columns :
From the clean - not impacted - state of column 8, it is clear that the port wing entered
the building on the right of this column. The odd state of column 18 will be examined in the
next page. It is however possible to draw conclusions from the state of columns 9AA, 16 AA
and 17 AA. The following pictures show these columns.
The sketch below shows the trajectory of the plane (plain purple line), the resulting
speed direction around columns 16-17 and column 9 (purple arrows), and the real bending
direction of these columns (green arrows).
The difference beetween the expected columns bending, i.e. parallel to the path
of the plane, and the real columns bending, is the key to understand how the
plane's wings folded during the crash.
The two sketches below show the vector speed composition which allows to estimate
the direction of impact on these columns. Three colors have been used :
On the starboard wing (left on the sketches), the part which impacts pillars 16 and 17 is the
engine. It's probable that this engine was itself colliding with the ground. It disconnected
the foot of columns 16 and 17 from the slab, leaving them hanging from the second floor slab
bent towards north. On the port wing (right on the sketches), pillars 10 to 12 are impacted
by the wing and totally broken. Pillar 9 is impacted by a thiner part of the wing and resists,
though bending towards the direction of impact, i.e. towards East (green arrow).
Note the greater size of rotation-induced speed on pillar 9 (whip effect). It would not be
surprising that beetween pillars 8 and 9, the wing tip speed was supersonic, which would
explain the totally "exploded" state of the wall there.
The crash reconstitution here above is coherent as well with the witness accounts
as with the laws of physics. The traces on the building, including the "apparently odd"
bending direction of columns 9, 16 and 17 or "apparently too small hole" account for the
"wings folding forward" effect that was described by some witnesses.
The hypothesis which fits the best to the whole damage done by the attacking plane is that
this plane had the size of a Boeing 757. It is logical and straightforward to conjecture
that it was B 757 number 644 AA of American Airlines, fleet number 5 BP, which had taken off
from Washington Dulles airport one hour before with sixty persons on board.