PUNCH-OUT HOLE “EXPLAINED” BY OFFICIAL ACCOUNTS
Adam Larson / Caustic Logic
The Frustrating Fraud
July 22 2007
Last updated/edited July 25
How exactly Flight 77's trajectory through the building wound up giving us the exit hole we’ve seen is left a bit vague in the official record. The American Society of Civil Engineers' Pentagon Building Performance Report shows a photo of the hole but gives no adequate explanation. Its terse summary: "there was a hole in the east wall of Ring C, emerging into AE Drive, between column lines 5 and 7 in Wedge 2. The wall failure was approximately 310 ft from where the fuselage of the aircraft entered the west wall of the building,"  The Arlington County After Action Report noted “the damage extended all the way through the inner wall of the C Ring, a distance of approximately 285 feet,” and showed a photo of the hole captioned “penetration through the inner wall of the Pentagon’s C Ring.”  An account of FEMA Urban Search and Rescue shoring/bracing of the building is the most detailed of these three reports. It explains that "a nine foot diameter exit hole was created in the wall of C ring and the remainder of the debris from the impact ended up in the alley between C ring and B ring known as A & E Drive," and elsewhere shows a photo of the "'exit wound' where the plane debris exited the C ring." 
These three reports, a few early press conferences, published eyewitness accounts, and a handful of photos constitutes the body of evidence on this hole. While it’s been widely seen and commented on, it has not yet been explained with any useful precision, and contradictory theories dominate to an unsettling degree.
Impact Energy Waves?
In October 2004, the National Geographic Channel program Seconds from Disaster proposed a novel theory by which shockwave pressure from the impact cause the punch-out hole. By this model, plane debris and heavy, exploding jet fuel, perhaps along with explosions of things in the building, gave off shockwaves that reverberated and crossed through the building’s first floor. Having no other exit point, these somehow directed themselves and whatever was in front of them to focus on that precise spot, punching the neat 9x11’ hole we’ve seen.  While this explains both the improvised exit and the lack of any major evident airplane parts, the official story has generally maintained it was physically caused by the plane, or some part of it, though which part has been widely contested.
Military District of Washington’s news service reported two weeks after the attack, mentioning that “an aircraft engine punched the hole out […] on the inside wall of the second ring of the Pentagon."  Though the quote has been widely republished, no other official sources support this claim. No debris seen there looks like engine debris.The piece’s author got the “second ring” part wrong (whether one counts A-E or E-A, C is the third ring), so maybe identifying an engine was an error as well.
As widely noted, Pentagon renovation spokesman Lee Evey explained implausibly during a September 15 press conference “the nose of the plane just barely broke through the inside of the C ring, so it was extending into A-E Drive a little bit. So that's the extent of penetration of the aircraft."  As Killtown wondered “how could the fragile nose of Flight 77 penetrate all the way through 3 reinforced concrete/steel hardened rings and punched out a hole through the inside wall of Ring C and leave no evidence of itself outside the punch-out hole?”  This seems unlikely, even given that the “hardened” walls from impact to exit really totaled only 22” of unreinforced brick and limestone [link forthcoming], but spanned between by about fifty damaged support columns and only one plane fuselage to absorb the other end of these blows.
What survived this was not precisely the nose cone, but more likely some element(s) of the nosecone assembly – landing gear, landing gear door, cockpit panel or cargo door – some tattered portion of the forward fuselage. As Jim Hoffman explained, in such an impact, “only the parts of the aircraft with the greatest density and total mass, such as the lower third of the fuselage, could be expected to penetrate far into the building. That part also has a small frontal profile - approximately the size of the punch-out hole.”  Of course there is no piece of debris anywhere near the size of the hole seen in any of the available photos, but the illustration is helpful. The fuselage had a lot of mass, tens of tons, and though it was under great stress, it didn’t simply disappear on impact.
It stands to reason that as the plane disintegrated, the densest parts of aircraft wound up at the deepest point of penetration. For example, the flight data recorder from the tail end of the plane was reportedly found just inside the punch-out hole.  The heavier elements from the front end would also come to rest around this point. The book Debunking 9/11 Myths identified the landing gear. The book cited Paul F. Mlakar, ASCE team leader and lead author of the Performance Report, who “saw the landing gear with his own eyes” during his early onsite inspections, for its explanation that:
“The hole was not made by an engine or the nose of Flight 77 pushing through the building’s interior - or a missile - but by the crashing jet’s landing gear, which was ejected beyond the bulk of the wreckage. […] As one of the heaviest and most dense parts of the plane, the landing gear flew farther than any other item in the wreckage and was responsible for puncturing the wall in Ring C.” 
Other photos and accounts seem to back this up by recalling or even showing a wheel, a tire, and even a massive landing gear strut, near the hole. But there are some serious problems with this theory as well, like the ASCE’s own Performance Report not identifying this alleged hole-puncher as such, which noted that "the landing gear" (all three sets?) were in fact found inside the building, hardly the best place to be after exiting through the hole into the AE Drive.  These questions will be summarized more fully in a [separate post].
ASCE and FBI Secrecy
Mlakar's ASCE study team “went to great lengths of detail down to individual columns” in the plane’s path, Russell Pickering noted, providing their own photos and personal damage assessment of nearly all of them. Yet they danced around the cause of the punch-out, as Pickering wrote, offering “not a single explanation for the exit hole.”  The three columns nearest the breeched wall - 1N-North, 3N-North, and 5N-North - remained un-photographed and listed in the report as “damaged per FBI.”  Pickering suspects falsification of the status of these three columns to hide inexplicably severe impairment. 
He speculated that “the building team […] weren't allowed back at the exit hole for some reason," and noted how "they indicated in the report why they didn't have photos of those columns and who gave them the damage report on the columns - the FBI.” The one photo they published of the exit hole itself was not one of their own, but also credited to the FBI, further indicating this area had special investigative significance to the bureau, although this could have many possible reasons. photo of the hole used by the ASCE, credited to the FBI (lower right, very small print.) 
 Mlakar, Paul F., Donald O. Dusenberry, James R. Harris, Gerald Haynes, Long T. Phan, and Mete Sozen. “The Pentagon Building Performance Report.” American Society of Civil Engineers. January 2003. ISBN 0-7844-0638-3. Page 28. PDF download link
 Arlington County After-Action Report. on the Response to the September 11 Terrorist Attack on the Pentagon. PDF downloaded from http://www.arlingtonva.us/Departments/Fire/edu/about/FireEduAboutAfterReport.aspx. The report bears no publisher or copyright info – it was compiled by Arlington County and Titan Systems Corporation, and released July 2002 according to this story: Weiger, Pam. “Pentagon report: After-action.” NFPA Journal. Nov/Dec 2002. http://findarticles.com/p/articles/mi_qa3737/is_200211/ai_n9114927/pg_1
 Titus, Leo J. Jr., P.E./Virginia Task Force One Urban Search & Rescue Team. “A Review of the Temporary Shoring Used to Stabilize the Pentagon After the Terrorist Attacks of September 11th, 2001.” May 3, 2002. Pages 9, 12. PDF download link: http://www.aesvn.org/resources/Pentagon-Shoring.pdf
 Seconds From Disaster – season one episode 12 “Pentagon 9-11.” National Geographic Channel. First Aired October 26 2004 http://en.wikipedia.org/wiki/Seconds_From_Disaster
 Military District of Washington. Press Release. (9/26/01) original url: http://www.mdw.army.mil/news/Commentary-Remembering_the_honored_dead.html. Accessed at: http://www.snopes.com/rumors/pentagon.htm