Some precise facts can be stated, either from witnesses accounts, or from physical
scars on items outside the Pentagon which were impacted by the arriving plane.
As this part of the Pentagon was under a renovation process, some annexes and materials
were disposed outside the building by the companies who contracted for this renovation.
Pictures, taken from the ground or satellite, are available to show what was disposed
in the impact zone in the first days of september. The aerial photo below, taken in May 2001,
shows what was present in the impact area. The purple arrow shows the crashed plane
trajectory.
Lower part of the plane, on whole port side, impacts trailors 1 and 2 and leaves nothing
visible from them.
The plane was a bit rolled to the left, as witnesses account. Questions arose on why there
was no damage on the lawn. The answer is straightforward : the lowest part of the plane touched
the ground just after having crossed this lawn, the lowest point (port engine) impacting
the ground level exactly where the lawn ends against the small wall surrounding the vent
structure.
The reason why the lawn bears no debris is also clear. Given the speed of the impact, the parts
of the plane which didn't get into the building through the openings (windows and crash created
holes) bounced outwards. They reflected like a liquid against the front, in a sector
approximately delimited by the two dotted purple lines.
As was ironically written in a web site,
the "pentalawn" could still
welcome golfers, but they couldn't have played in the lawn located in the upper left
part of the above picture.
On the starboard side, the engine impacted the fence, near it's corner, and the electric
generator. A witness said the engine "went through the generator as through butter".
The generator was shifted aside in the shock, it's front part destroyed.
Remark : Some critics of the pictures above appeared on the web, like on
this killtown site page.
I agree with these critics. Given the distance, the flap track responsible for the gouge
on the top of the generator is probably not the one I have labeled "2" on the picture
above but the next one going towards the wing tip. I'm sorry, I haven't a picture of a
757 from this same angle to show it.
From the pictures above it can be seen that the lowest part of the engine should be
approximately at three to four feet from ground, as it is from the tarmac on a plane
laying on it's landing gear. The fact that the lawn is intact at the left is a
confirmation that the landing gear was up.
This generator later burnt, as can be seen on the image below taken a few minutes
after the crash.
A closeup with luminosity and constrast enhancement shows the bump on the higher part
of the generator, and also what could be an impact on the right.
Two different views of this
generator,
left general view, right closeup with luminosity
and contrast enhancement, show that a scar has been created on the top,
just behind the bump that can be seen on the picture above. This scar
seems to get deeper when going towards the building, which indicates that this part
of the starboard wing was on a descent trajectory. This scar is straight and it's
angle is coherent with the position of the generator parallel to the pentagon's front
before the impact. The shock, as well of the engine as of the part under the wing
which made this scar, was very short : if the plane flew at 200 m/s, all these
damage on the generator were made in about 30 ms. In this short time, the initial
velocity given to the generator by the impact, not so tremendous as it was moved
aside only a few meters, was much lower than the plane's speed, which allows to
consider that the generator stayed in it's initial position during the shock.
The angle of this scar regarding to the generator axis (~55 degres) is therefore
coherent with the plane's flight axis. Click to get a closer / broader view.
The picture below shows the little damage done by the port engine on the protection wall
surrounding the ventilation structure (left yellow mark). On the right of the picture,
the part of the fence left intact close to the starboard engine.
On this picture can be seen also the impact point of the nose of the plane on
the building (center yellow mark) and the impact point of the starboard engine on
the front of the building (right yellow mark).
The comment and photo here below are extracted from Sarah Roberts web site :
Aerial photos taken on 9/14/01 give an unobstructed view of the vent
structure. They show a hole in the south wall while the low wall to the east is
missing. Construction workers are repairing the damaged section in the
intervening area. These observations suggest that the engine hit the southern
section of the vent structure and demolished the low wall to the east -- a path
consistent with the plane's trajectory.
[Tech. Sgt. Cedric H. Rudisill; Original Source:
http://www.freewebs.com/stjarna/www.defenselink.mil/photos/Sep2001/010914-F-8006R-003.html]
One of the oddities of this crash is the lack of serious damage on five of the six
cable spools that were disposed just on the plane's axis. It is probable that the
plane's belly just skimmed five of these spools and that they were pushed in the direction
of the pentagon, along the axis of the plane's last meters before crash, by the
slip stream. The sixth one was probably touched and was found
more damaged close to the building. A web site, same ironic style than "pentalawn",
ironized on these undestructible spools made of "pentanium" alloy : not to be
taken too seriously...
All the traces found on various items hit before the front of the building
account for a twin engine airliner impact, as shown on the picture
below.