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.

After having hit the lamp poles, the plane impacted the following structures :

  • Left (port) engine : impact on the corner (nearest to arrival axis) of the ventilation structure.
  • Port wing (or engine ?) : impact of a cover structure at the nearest from Pentagon part of the ventilation structure.
  • Right (starboard) engine : impact on the fence and on the front part of the electrical generator.
  • Starboard wing (more exactly a metal structure at the lowest part of the wing) : impacts the top of the electrical generator.
  • Plane's belly : impacts the cable spools, or just skims them making them move under the air pressure.
  • 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.

    Damage on fence and generator Starboard side of 757

    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.

    2nd explosion

    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.

    Generator closeup

    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.

    impact zone

    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:]

    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.

    pre impact