911  2001
An Attack by Political Extremists using Hijacked Airliners
J. I. Nelson, September 2011
I hate them.
Ten years later, my greatest consolation is that
the Arab world has moved on without them -- 
they are irrelevant.


Aerial view of WTC Twin Towers from river before 911
The World Trade Center's (WTC's)  twin towers before the attacks of Tuesday,  11 September 2001.
The North Tower (left; radio/TV broadcast mast on top)  had the street address 1 WTC
and is often referred to as Tower 1.
The North Tower (left) was hit by a plane flying in from the left (coming out of the north to hit the north face);
The South Tower (right) was hit by a plane flying from right to left to hit the south face visible in photo.
Both planes flew down the Hudson River (foreground) from the left, and banked into the towers.
For the South Tower, this was a dramatic 180 deg, low-altitude turn.

8:40    Someone at the FAA places the first FAA call to the  Northeast Air Defense Sector of NORAD. The following exchange takes place:

FAA: Hi. Boston Center TMU, we have a problem here. We have a hijacked aircraft headed towards New York, and we need you guys to, we need someone to scramble some F-16s or something up there, help us out.

NORAD: Is this real-world or exercise?

FAA: No, this is not an exercise, not a test.

JIN: The nine minutes of advance notification that Flight 11 had been hijacked prior to its destruction of the World Trade Center North Tower was the most time that NORAD had to respond for any of the four hijacked flights.  

Counting only the F-15 Eagle, the F-16 Falcon and the F-18 Hornet, we had over 1,500 fighter jets in active service, at a construction cost of  over $45 billion.  Not a single one intercepted a single hijacked flight.  Today we have ca 600 more F-18s,  and the new F-22 Raptor is flying (another $25B).  All that money is bound to help.  

WTC North Tower-Outline O fPlane Entry In Facade 93-98th floors -Reuters.jpg
They never learned how to land in flight school.
The outline of American Airlines AA11 in the north face of the North Tower (WTC 1),
spanning floors 93 to 98.

8:46:26  The seismographs at the Columbia University Lamont-Doherty Earth Observatory record the impact of  American Airlines flight 11.  At about 466 mph (recent calculations put the figure higher), the Boeing  767's aluminum fuselage shreds and the two steel alloy engines hurtle across the tower.   Flight 11 was fueled for a Boston to LA flight when it took off 47 minutes earlier.  A 767-223ER weighs ca 300,000 pounds when 95% fueled.  The tower sways for many seconds, but stands.  

WTC 1, North Tower-Jet Fuel Firebal at Moment of AA11 Plane Impact l-Jules + Gedeon Naudet.jpg
A rare photo of the first Tower being struck.
Jules and Gedeon Naudet were doing on-locaton filming when they heard a plane
much too low and loud.  Both brothers swung their cameras up and
captured the the only good footage of flight AA11's impact on the North Tower.
This is a single cropped frame from the film, which begins immediately before impact.  

"We are in rapid descent ... we are al over the place.  I see water. I see buildings. I see buildings! We are flying low. We are flying very, very low. We are flying way too low. Oh my God we are flying way too low. [Long, deep inhalation.]  Oh my God!" (static)
--Amy Sweeney,  flight attendant AA Flight 11
Impact 8:46:26

In older office buildings, the staircases were often shielded with poured concrete.  In both World Trade Center Towers, the staircases were shielded with two layers of "fireproof-grade" gypsum wallboard.  The North Tower is hit squarely, and all three staircases and the elevator shafts are taken out.  1344 people are trapped.  

8:50 - 8:51: First documented jump from the Towers: North Tower ( north face, 93rd floor).

011 WTC South Tower UA Flight 175 Zeros In--FrankJDenicolaNYT.jpg

United Airlines flight UA175 zeros in on WTC 2, the South Tower.
The plane,  a ca 300,000 lb 767-200ER going an estimated 586 mph, hit the tower's south face at 9:03.
 With the North Tower already hit, eyes were on the sky and many photos were taken.



911 - South Tower - UA 175 plane Against Sky - Both Towers standing  
click to enlarge   (photo: Sean Adair - Reuters)


911 Plane against sky flies into South Tower
Naka Nathaniel, NYT

911 Flight UA175 against blue sky heads for WTC2 South Tower
ABC via APTN
We are looking south at the north face of the North Tower (with radio/TV mast),
where AA Flight 11 entered.  
On the right, UA Flight  175 is banking off the Hudson River
 to come up against the south face of the South Tower,
which we cannot see.


911 Flight UA175 zeros in on WTC2 South Tower
photo: Carmen Taylor via KHBS - KHOG-TV



911 - Fireball engulfs WTC2 South Tower  
Chao Soi Cheong - Associated Press.  Click to enlarge.

We are looking at both Towers' eastern faces, lit by the morning sun.
It is 9:03 AM.  The South Tower (2 WTC, left)  has just been  hit from the left by another 767, UA 175 that took off for LA from Boston 49 minutes ago.  

The plane's fuselage shreds, and the two steel alloy engines hurtle across the Tower, but the plane has entered obliquely and one of the three staircases remains (barely) passable.

A tidal wave of shredded aluminum and fuel sweeps entirely across many floors between the 78th - 84th levels. The tidal wave of debris runs south to north,  mostly along the eastern face, and breaks out on the northeast corner (photo).  It is this eastern face which will later start the collapse.  

The debris continues to burn long after the jet fuel has disappeared in a fireball. It is the debris that keeps the fire going long enough to soften structural steel and doom 2 WTC,   Fifty-six minutes later (9:59), the South Tower collapses.

Jules and Gedeon Naudet got photos of the North Tower being struck almost by accident, but many people photographed the second strike.

South Tower - Jet Fuel fireball a few seconds later
Chao Soi Cheong - AP
The South Tower fireball and additional moment after impact.  
Only parallax from this ground-level view makes the flames appear to explode against the neighboring  black building.  They are actually much higher (78th - 84th floors; see other photos.  

SouthTower-Je tFuel Fireball-3--Chao So iCheong - AP
Chao Soi Cheong - AP
Having burned long enough to create an upward convection current,
the South Tower fireball now rises.  

The fireball ignited the shredded contents of all the offices on a given floor, and those materials, not the aviation fuel, sustained the blaze long enough to bring the building's structure steel to red-hot temperatures.  Although there are special alloys (e.g., cobalt-vanadium steel)  that remain hard at red heat, their expense and other limitations confinetheir use to cutting tools in manufacturing.  In older office towers, poured concrete was used to shield key structural steel elements.  In the World Trade Center Towers, the sprayed-on steel fireproofing was just blown away.

911 WTC South Tower - Moment Of Impact -- Shower of Debris 9:03AM
 Spencer Platt - Getty Images
Photo just after the 9:03AM impact of UA175, a nearly fully-fueled Boeing 767-200ER jet, into the South Tower.  The plane flew into the opposite side of the left (south) Tower; we are looking at the entry wound of the right (north) Tower.  The planes attacked 17 minutes apart from opposite directions.  

911 WTC towers both hit; fireball just after 9:03 impact of Flight UA175 on South Tower
Spencer Platt - Getty Images

The fireball grows older and rises.  On the left of the left Tower, no plane struck.  The force of the explosion is blowing out all the windows.  Towers will never be built again with the flaws which led to these towers' collapse, and  trapped nearly 2000  with no route of escape.  But let us note that the impact of aircraft weighing about 300,000 lbs each and traveling at over 466  miles per hour did not topple either structure.  



911 - Both WTC Towers Smoking, Empire State Bldg in foreground   click to enlarge  (Photo: Marty Lederhandler, AP)

The 9 o'clock hour in New York City, 11 Sept 2001.  It is after the South Tower (left) has been hit at 9:03, and before it collapses at 9:59.  Four minutes after it was hit at 8:46, people began jumping from the North Tower.  For nearly a quarter hour, this chilling spectacle drove thosands to the South Tower elevators while they still worked.  
Although the South Tower was hit lower (78-84th floors vs  93-98th), fewer people were caught above the impact area (about 600, vs 1344 in the North Tower).



People Aghast at StPatricks Cathlook stare down 5th Ave

COLLAPSE

BRIAN CLARK:
He said, "You know, I think those buildings could go over."
And I said, "There's no way." I said, "Those are steel structures."
And I didn't finish the sentence.

Brian Clark (World Trade Center Survivor, South Tower, 84th floor office) is one of only 18 people who found the 1 of 3 staircases that was passable, and got down it before the fires burned through the sheet rock (two layers, "fireproof grade") that failed to protect the escape route.   In the North Tower, all staircases were disabled, because the plane hit squarely and the tidal wave of fuel and debris --and  perhaps the heavy airplane jet engines as well -- went straight to the core.   



911 - Collapse - WTC South Tower-Tipped  
Click image to enlarge.
Flight UA175 hit the South Tower obliquely (left to right), snow-plowing shattered offices and everything in them
into a wall of burning debris along the eastern facade (foreground), which is now (9:59) bucklng.  
The entire support structure failed, so what you see tipped now came straight down
without falling completely out of the tower's ground-floor footprint.  




911 WTC: Collapse of South Tower. Tipps as east wall crumples.
 Photo: Amy Sancetta - AP. 

The South Tower collapses as its east wall crumples.
Foreground: Banker's Trust Building, aka Deutsche Bank Building, torn down 2010/2011
after it was deemed still standing, but irreparable.  



911 WTC South Tower's progressive collapse in full swing.
PHoto: Jose Jimenez, Primera Hora (Getty Images)

The progressive collapse of the South Tower is in  full swing.
Both towers pancaked.  




911 Collapse of South Tower as Outer Columns BreakApart
photo: Associated Press (AP)

The outer columns break apart as the WTC South Tower collapses.


911 - WTC South Tower Collapse-Huge Chunks Fall Onto Marriott Vista hotel, 3WTC   

Click to see an enlarged, less-doctored version of this great photo by a great photographer.
The collapsing South Tower hurls huge chunks of itsouter columns on 3 WTC, the Marriott Vista hotel.
The 825-room hotel was destroyed.


911 WTC Collapse of South Tower -- Debris Cascades Down  
Photo: Shannon Stapleton - AP  click to enlarge
 
The South Tower: hit last, collapses first.



911 WTC North Tower pancakes at 10:28, 1 hr 42 min after being hit
photo: Reuters
The North Tower pancakes 1 hour and 42 minutes after being hit at 8:46.



911 WTC North Tower collapses in place, beginning at 10:28 AM.
photo: Reuters.
The North Tower begins to collapse at 10:28, 1 hour and 42 minutes after being struck.
Although flight AA11 hit squarely and severed all staircases and elevator shafts,
the tower that was hit first fell last.  

  




911 WTC Collapse of North Tower begins - aerial view  
Photo: NY Police Dept. - Detective Greg Semendinger - AP
Click to enlarge.  
The second tower collapses, beginning at 10:28.

The reddish building lower right is 7 WTC, a 47-story skyscraper
above a Consolidated Edison electrical substation,
housing Solomon Brother, ITT Hartford Insurance, the Securities and Exchange Commission (SEC) offices,
and other tennants.  It collapsed at 5:21 pm on 9/11 the same way as the towers did:
fires weakened structural steel insufficiently protected by masonry.
Low water pressure prevented the building's sprinkler system from suppressing the fire.
The 7 WTC collapse in turn damaged the BMCC's (Bureau of Manhattan Community College) Fiterman Hall.
The college dorm was demolished in 2009.  


911 WTC Collapse of North Tower throws silicate ash over entire lower Manhattan area - aerial view  
Photo: NY Police Dept. - Detective Greg Semendinger - AP
Click to enlarge.  
The collapse of the second, North tower.  

The dark building  (left) is the Banker's Trust Bldg (later called the Deutsche Bank Bldg).  
It was deemed irreparable; demolition was completed Jan 2011.
Close to the Hudson River (top) is the World Financial Center,
where the twin, green-topped American Express and Merrill Lynch Buildings survived.  




BldgNo7CollapsedByAdjacentNTwr-nextAM-TimothAClaryAgenceFrance-Presse.jpg



















Front page of the San Franscisco Examiner on 911


Witness To North Tower Collapse on 911  
click to enlarge
Witness to the North Tower's collapse (photo: Shawn Baldwin, AP)




911 Timeline by 911 Commission
Soon after the attacks, FBI Director Robert Mueller announced "there were no warning signs that I'm aware of that would indicate this type of operation in the country."  For me as an American, the most important lesson of 911 is that my government failed to protect me and never apologized for it.