9/11: Pentagon Facade Damage Fits a 757

Punctured Walls Admitted Most of a 757

The portions of the Pentagon’s facade punctured by the crash are easily measured by combining data from several different photographs, both before and after the collapse of the section. Several photographs by Jason Ingersoll provide detailed views of right portions of the impact zone. Other photographs show the left portions of the impact zone. Together, these photographs show that the facade was punctured over a wide swath on the first floor and a much smaller extent on the second floor.

Measuring the punctured regions shows that the facade was completely punctured for a width of 96 feet on the first floor and 18 feet on the second floor. Punctured areas were bounded by columns and floor slabs. This is natural since the columns and floor slabs were constructed of steel-reinforced concrete, whereas the window bays spanning them were brick walls reinforced with steel window frames and Kevlar mesh as part of the renovation program.

On the first floor, the primary puncture extended from column 8 to column 18. Three leaning objects in the first floor space left of the hole center are often assumed to be displaced remains of columns 15, 16, and 17. However, this analysis shows that those objects are more likely to be fallen pieces of the second floor slab than columns. Thus, it appears that the crash initially left a first floor hole that extended unobstructed for 96 feet. Surviving column 18 marked the rightmost extent of the hole, but to the right of it is another hole extending to column 19. Thus the total width of punctured walls on the first floor was at least 105 feet.

On the second floor, the puncture extended from column 13 to column 15. Photographs show a hanging object in the position of column 14. This appears to consist in part of remains of the steel reinforcements that were part of column 14.

Breached Limestone Marks Profile of 757’s Wings

Beyond the areas of the punctured facade walls were extensive regions in which the facade’s limestone facing was breached. Post-crash photographs show regions of missing limestone facing from about four to eleven feet above the ground and extending to at least 40 feet to the north of column line 8.

Photographs also show extensive damage to the south of the impact punctures, with most of the damage to the south of column line 19 being above the first floor.

Although the damage beyond the impact punctures appears to be consistent with the impact of the outer portions a 757’s wings in both degree and extent, many observers think that the impact should have left a clear imprint of a 757’s profile on the facade, much as the impacts of 767s left their profiles in the Twin Towers. This is not a persuasive argument against the crash of a 757:

• The Twin Towers had curtain walls of box columns and spandrel plates of steel between 1/4 and 3/4 inches thick at the crash zones, and the walls were clad with delicate aluminum sheeting. In contrast, the Pentagon had heavy masonry walls faced with limestone slabs about 5 inches thick. There is no reason to expect that the crash of a jetliner should have produced similar impact scars in these very different buildings.
• The physical integrity of the Pentagon attack plane on impact is unknown. It is possible that either or both of the wings was severely damaged by the impacts with the lamp poles, generator, and retaining walls on its final approach. Portions of the wings may have separated prior to impact, changing their impact profiles.
• Other events, such as the possible detonation of a defensive weapons system described below, could have further altered the crash profile.