Air War - Proof Readers Needed!

[gumboot]

Hi folks,

I've finished the first step in writing my final NORAD/FAA paper titled "Air War". At this stage I have covered everything up to the sequence of events on the day itself, which I'm still not sure how to actually present. Categories covered are:

THE ELEMENTS IN THE SYSTEM
-The Federal Aviation Administration
-The North American Aerospace Defense Command
-The Continental US Radar Network
-At-sea Operating Areas

THE SYSTEM IN PEACE AND WAR
-Peace time responsibilities and procedures
-Aircraft Piracy
-Active Air Defense Missions and Air Defense Emergencies

CASE STUDY – The Intercept of N47BA

THE SYSTEM ON THE MORNING OF SEPTEMBER 11
-Assets in play
-Wargames

I'm after anyone who is willing to read through the first completed sections and offer some proof reading and fact checking for me.

Currently I also don't have any references logged in, mainly because I'm not sure how I want to manage my references either (quotes and links as I go along, or footnotes?).

So some feedback generally on the document, some feedback on how you think I should use references/quotes and some feedback on how you'd like to see the timeline of the day itself laid out would be appreciated.

Any takers?

The document is a 1.9MB PDF so best bet is going to be if I email it to people, so maybe PM me if you want to help out. Currently sitting at 32 pages and 14,000 words.

[Reheat]

I'll help, Gumboot. Let's do the arranging by PM.

[Gravy]

Hey, cool. Sign me up for that, if you like. nyctours(at)gmail.com

[ElMondoHummus]

PM'd you about this.

[SpitfireIX]

I'll be glad to help, too; I was thinking of making some proofreading suggestions on the excerpt you posted. I have a B.A. in American and European history, and minored in English, so this is right up my alley. Plus I know more about British/Commonwealth English than probably 99.9% of Americans. :D I'll PM you my email.


ETA: I also read aircraft and other accident reports for "fun" (for lack of a better term), so I'm fairly conversant with ATC operations, for an amateur.

[LashL]

Count me in as another volunteer proofreader if you like, gumboot.

[USAFMXOfficer]

Gumboot - Love to help, I'm an Air Force logistician but with more than a rudimentary knowledge of NORAD/FAA command relationships and ROE.

[gumboot]

Thanks everyone I'm sending them out now. :D

Just a note, obviously I'm a New Zealander so we use proper spelling... ;) However I don't want to change spelling if I'm naming an actual organisation etc, so I've decided to keep things simple and much as seeing all those z's makes me feel unclean, I'll be going with American spelling throughout the document.

Currently I think it's a bit of a mix of American and regular English spelling.

[gumboot]

I think I have enough general proof readers now, however I'm still happy to pass the document along to anyone with specific experience in the subject matter for fact checking and so forth - so anyone with FAA or DOD experience.

Much of the document is of course my interpretation of the references I have available, and if people more knowledgeable than me can spot errors in that interpretation that's the sort of errors that need cleaning up!

Also I've been trying to determine a fuel consumption rate for a fighter at cruise speed, but it's not coming across. I would guess (perhaps incorrectly) that cruise speed is achieved by setting a certain % throttle, but does the specific fuel consumption rate scale back linear? - So that 80% throttle would consume fuel at 80% of the full dry thrust rate. Or would 80% throttle use the same specific fuel consumption rate as full dry, but the total pounds thrust produced is only 80% effectively resulting in an 80% reduction in fuel consumption.

[USAFMXOfficer]

Gumboot - I still have several contacts on the F-15 weapon system team at Air Combat Command, I will see what I can find out. It will be F-15 specific but we might be able to extrapolate to the single-engined F-16.

- USAFMXOfficer

[gumboot]

Gumboot - I still have several contacts on the F-15 weapon system team at Air Combat Command, I will see what I can find out. It will be F-15 specific but we might be able to extrapolate to the single-engined F-16.

- USAFMXOfficer


Thanks. They both have the same engine but the F-16 has a thrust/weight ratio of 0.898 while the F-15 is 1.12. I assume that's in slick configuration.

[USAFMXOfficer]

From Wikipedia:

Military thrust: 0.76 lb/(lbf·h) (77.5 kg/(kN·h))
Full afterburner: 1.94 lb/(lbf·h) (197.8 kg/(kN·h))

That's 0.76 lbs fuel consumption per 1 pound thrust per hour.

I don't know if it is a linear relationship between throttle setting (i.e. cruise vs military vs full afterburner), I will check tomorrow at work.

BTW, the F100 is a pig, at least the early version the F100-PW-100. Maintainers spend many hours on this engine keeping it in commission. The follow-on -220 and -229 (in the F-15E) are much more maintainer-friendly.

If you ever get a chance, you need to see an F-15 full afterburner takeoff at night. Incredible. I'll try to find a couple pictures.

[TjW]

Just to nitpick: It shouldn't matter. Draggy or clean, it will weigh the same. Draggy or clean, it should produce the same thrust.

[Reheat]

Also I've been trying to determine a fuel consumption rate for a fighter at cruise speed, but it's not coming across. I would guess (perhaps incorrectly) that cruise speed is achieved by setting a certain % throttle, but does the specific fuel consumption rate scale back linear? - So that 80% throttle would consume fuel at 80% of the full dry thrust rate. Or would 80% throttle use the same specific fuel consumption rate as full dry, but the total pounds thrust produced is only 80% effectively resulting in an 80% reduction in fuel consumption.

The % 80 RPM is simply a throttle setting related to % 100 RPM. It has nothing at all to do with fuel consumption or thrust produced. Cruise speed would vary depending upon mission requirements. i.e. Simply going from point A to point B would be at a recommended cruise speed. Usually, however, there is a TOT to meet or a target to intercept which might dictate the speed. Typical cross country cruise would normally be in the high % 80 range for most fighters. Most of the modern fighters will reach supersonic speeds with Mil Power (% 100 RPM).

Fuel consumption/thrust produced is not linear and will vary with the specific aircraft. Although I have flown the F-16 I don't remember details like that, not even close.

I don't know if it is a linear relationship between throttle setting (i.e. cruise vs military vs full afterburner), I will check tomorrow at work.

I can assure you it isn't linear.

Just to nitpick: It shouldn't matter. Draggy or clean, it will weigh the same.

What? With weapons or fuel tanks the aircraft weighs the same as it does in a clean configuration? "Slick" means no weapons or fuel tanks, it does not necessarily mean no drag devices. That must be the confusion.

Draggy or clean, it should produce the same thrust.

Correct, but obviously the resulting speed will be different.

[TjW]

Okay. I was thinking flaps, wheels, etc.

[gumboot]

For anyone who is interested, I got my engine specs from here (http://www.jet-engine.net/miltfspec.html).

[USAFMXOfficer]

Gumboot - Wow! Great site! The table is a little hard to read (wish it was excel so you could freeze panes), but great info!

Thanks,

[Wildy]

If you still need people to read you can count me in. Hopefully I will be able to understand Kiwi :D.

[Reheat]

Folks, as Gumboot indicated above he does not need English Majors to critique his paper. He is an excellent writer and needs no help at all in this area.

He needs TECHNICAL CRITIQUE from folks familiar with FAA/ATC Procedures, DOD stuff, NORAD, aircraft stuff (fighters), etc. or those willing to research these areas for verification of existing information, errors and suggestions to make it better.

[gumboot]

Thought I might as well use this to share interesting updates.

I've uncovered a draft Department of Transportation plan from July/August of 1997 which details plans by the FAA to completely decommission all internal CONUS primary surveillance radar sites.

While the purpose of the paper in itself is interesting - in that it reinforces the idea that US air defense was in a process of "winding down" after the Cold War - what's really interesting is that as part of the paper they detail the findings of an FAA impact study that details the affect of deactivating all primary radar.

Not surprisingly, the paper makes no mention whatsoever of hijacked airliners being used as weapons.

The only real concern they have is that they won't be able to help aircraft is distress as effectively, and that they won't be able to track transponder failures.

To both problems they determine that failures are rare and almost exclusively occur in small aircraft flying at low altitudes, thus primary coverage often can't pick them up anyway. In the extremely rare cases of Class A Airspace failure, they suggest merely that non-radar separation rules are applied, resulting in a decrease in service.

What is most telling here is that prior to 9/11 the FAA obviously felt no concern whatsoever at having no primary coverage at all.

[Architect]

I think I have enough general proof readers now

Make sure they're from countries who know how to spell properly......



;)

[Mr.D]

Make sure they're from countries who know how to spell properly......


Why? Is this one of those things where the Brits stick in an unnecessary 'u'?

P R O U P E R L Y ?!?

;)

[I can't believe I delurked for this stupid joke]

[SpitfireIX]

Make sure they're from countries who know how to spell properly......



;)


Sorry, Architect, but he's writing in American English. :p


BTW, gumboot, sorry I haven't updated you on my proofreading; I've been working a lot lately (plus I misplaced the copy I printed and was halfway through marking up for several days. :o I hope to finish up tomorrow evening while I'm watching my friend's kids during her long class.

[gumboot]

I've completed the first draft of the most important section of my paper, so I'm posting it here to get some more thorough feedback.

This is the "analysis" section where I look at the timeline of events in more detail and make some conclusions about how the system performed on 9/11.

PART SIX
ANALYSIS

The following section analyzes the events of 9/11 in more detail in order to draw some conclusions about how the air defense system functioned. I have divided this section into three broad categories that reflect three distinct stages of the day.

The first is the initial response to the attacks. This analyzes how well the existing systems worked in responding to initial reports of aircraft hijacking. This section covers up until 0903EDT.

The second section covers the system’s gradual realization that what was occurring was not a conventional hijacking but something wholly new; multiple coordinated suicide hijackings. The key moment was 0903EDT when UA175 was witnessed on television striking the South Tower of the WTC in what was quite clearly a deliberate act. However due to the compartmentalized nature of the air defense system the actual process of realization came at different times for different elements.

The final section analyzes how the system responded once it was clear they were dealing with a unique and unexpected threat. This is the period in which the air defense system had to improvise a new method for addressing the unfolding situation.

At all stages of this analysis I will attempt to make clear distinctions between what was actually occurring and what was known or believed by the various elements of the air defense system. Any defense system can only function in response to the intelligence it is receiving.


6.1 The Initial Response
The September 11 attacks began at 0814EDT. The daily rise in morning air traffic was beginning on the East Coast, and Air Traffic Controllers at Boston, New York and Washington ARTCCs were busy handling the increasingly busy skies above them. At 0814 an air traffic controller at Boston ARTCC experienced a momentary set back – one of the flights he was handling did not respond to communication. It was American Airlines Flight 11, a Boeing 767-223ER flying from Logan International Airport to Los Angeles International Airport.

Over a period of several minutes the controller made repeated attempts to reestablish communication with the aircraft. During the initial phase the controller would not have any reason to be concerned about AA11. Communication errors are not uncommon and are usually resolved in a matter of minutes. Typical causes include pilot inattention, interference, or incorrect use of equipment.

However as the minutes passed the situation would slowly begin to be considered more serious, with prolonged non-communication suggesting a radio failure on board the aircraft.

Seven minutes after loss of communication, the situation became more serious. At 0821 AA11’s transponder was turned off. Immediately, the data block attached to AA11’s radar return vanished, taking with it information such as the aircraft’s altitude, flight number, and beacon code.

The most likely cause of such an incident is some sort of power or system failure on board the aircraft. Activation of primary radar coverage can immediately establish that the aircraft is still airborne, ruling out some sort of catastrophic mid-air break up.

Three minutes later the situation again changed when Boston ARTCC received a series of three transmissions from AA11. The voice the controller heard was not the pilot, and appeared to have a middle-east accent. He appeared to be giving instructions to the passengers.

This is the first indication – at 0824 – that an incident has occurred on board AA11 and the pilots may no longer be in command of the aircraft. With the transponder deactivated, the FAA cannot receive the 7500 beacon code which would confirm a hijacking was underway.

At about the same time as the transmissions, AA11 deviated from its assigned flight path, and began a turn back towards New York City. This was in keeping with the transmission from the flight which stated the hijackers were returning the aircraft to the airport. A traditional hijacking is a hostage situation in which a group of people are held as a bargaining tool to gain specific objectives. The assumption is that a government will relent to the hijackers’ demands in order to secure the release of the hostages. An aircraft offers an attractive hijacking prospect as it is a completely contained environment. Thus the hijackers are able to execute the most vulnerable phase of their operation – seizure of the hostages – while confident that no one can interfere with them, and that hostages cannot escape. Due to the vulnerable nature of an aircraft in flight, air crews are trained to cooperate with hijackers and to make getting the aircraft on the ground their priority.

An aircraft hijacking will typically follow one of two paths – the first is that the hijackers will direct the aircraft to be landed at a specified airport where demands will be made of the authorities. The second is that the hijackers will direct the aircraft to be flown to a friendly state where they are seeking asylum.

The comments of the hijacker on AA11 and the flight path of the aircraft suggested the former scenario – the hijackers would instruct the pilots to fly the aircraft to an airport, land, and make demands of the US authorities in exchange for the release of hostages.

The presence of a hijacker in the cockpit, and the voice of a hijacker over the radio, were not in themselves signs of an irregular hijacking. Hijackers typically instruct pilots to follow their directions, and may do so with direct threat of violence. Hijackers may also wish to communicate with the passengers to ensure their cooperation, as appeared to be the case with AA11. The hijacker’s error in sending their comments through the radio rather than the aircraft’s PA could alternatively be an error on the hijacker’s part, or an act of subterfuge on the part of the aircrew, attempting to secretly alert the FAA to their situation. Initial media reports after 9/11 suggested this very scenario, until it became clear the hijackers had disabled the pilots immediately and piloted the aircraft themselves.

In the event of a typical hijacking the priority for Air Traffic Control is to ensure that the errant aircraft does not collide with other aircraft in the densely packed airspace. Sterilising airspace along the aircraft’s route is standard procedure, and Boston ARTCC immediately began doing this. In addition likely destination airports were alerted so that they too could sterilize their facilities in anticipation of the aircraft’s arrival.

Boston ARTCC began notifying the chain of command that AA11 was a suspected hijacking headed into New York immediately after the suspicious transmissions were received. The FAA’s ATCSCC in Herndon received word of the incident at 0828 and they in turn notified FAA Headquarters at 0832.

At this stage, 18 minutes into the hijacking, the only indication that the situation was anything other than a typical hijacking was the deactivation of the aircraft’s transponder. Without this Boston ARTCC could not determine AA11’s altitude. Based on this single discrepancy, Boston decided to deviate from normal protocol. In a typical hijacking the decision to involve a military escort would be made at FAA Headquarters and passed to the NMCC. Instead, Boston ARTCC contacted Cape TRACON at Falmouth, Massachusetts and asked them to request a fighter escort from the alert fighters at Otis Air National Guard Base.

This request was received at 0834. The call was received by the Massachusetts Air National Guard Director of Operations – Lieutenant Colonel Timothy Duffy. That day he was an assigned alert pilot with the 102nd Fighter Wing and would therefore be one of the pilots responding to the request. It was not normal to receive a scramble request directly from the FAA – normal protocol was for a scramble order to be received from NORAD. The situation required further investigation, however if a scramble was authorisied he would need to be ready for it. Duffy therefore transferred the call through to the Squadron Commander on duty that day. The other pilot on duty that day was Major Daniel Nash and he was assigned lead pilot. However the pilots decided together than Duffy would take the lead as he had previous experience escorting a hijacked aircraft in February 1993 when a Lufthansa flight was hijacked over the Mediterranean and diverted to JFK Airport in New York.

Meanwhile Boston ARTCC’s military liaison had arrived at the Operations Floor and immediately contacted NORAD’s North East Air Defense Sector to request a fighter scramble and to see if NEADS could establish the aircraft’s altitude. This call came at 0837.

Despite these unorthodox scramble requests, the military acted immediately and the Mission Crew Commander – Major Kevin Nasypany was immediately paged to the Operations Floor at NEADS.

The Squadron Commander at Otis contacted NEADS shortly afterwards and NEADS were able to confirm that they had received word of the hijacking and were working on it. It was at about this time that Duffy appeared at the Otis control tower to notify the Squadron Commander that he and Nash had decided to switch roles for this incident if they were scrambled. The Squadron Commander and Duffy both agreed that the two pilots should make their way to their aircraft on the assumption that they would be scrambled.

As soon as Nasypany arrived at the NEADS Ops Floor he ordered the Otis fighters to battle stations. This directs the pilots to climb into their aircraft and be on standby to take off. Because of the anticipation from the personnel at Otis, Nash and Duffy were already half way to their aircraft when the battle stations order was received.

At the same time Boston ARTCC were trying to determine AA11’s altitude, and to do this were asking nearby aircraft to be on the look out. The pilots of one particular aircraft – United Airlines Flight 175 – reported that they saw AA11 at an altitude of about 28,000 or 29,000ft. Boston ARTCC directed UA175 to change course to avoid AA11. At this time AA11 began a rapid descent towards the ground, however Boston ARTCC did not know this at the time as they did not have altitude data from the flight.

As AA11 descended the Tracking Technicians at NEADS desperately tried to find the aircraft amidst the dense noise of ground clutter along the eastern seaboard. With their radar sensitivity maximized to detect infiltrators at low altitude over the ocean, the landward sectors of their radar were an indecipherable storm of primary radar returns. One of them was their target aircraft.

At 0840 AA11 passed into New York ARTCC airspace, as did UA175. Immediately the military were on the back foot as the centre they were communicating with was no longer handling the aircraft.

Then at 0842 AA11 dropped below primary radar coverage and vanished from radar scopes. Controllers at Boston and New York and Tracking Techs at NEADS desperately tried to find the aircraft. With no confirmed radar returns, and with the aircraft in some of the most dense air traffic in the world, it became imperative that fighter aircraft intercepted the airliner to provide vital information on its location.

At 0844 NEADS decided that they didn’t have time to wait for an official scramble order, nor for the flight to be located on their radars. The MCC ordered the fighters from Otis to scramble to the aircraft’s last known position. From there the fighters would, through a process of elimination, cross reference every single radar return until they found the airliner. The fighters – with their own powerful radars and the pilot’s situation awareness – would have a much easier task than the Tracking Techs.

The scramble order was received by Otis ANGB at 0846. At that moment AA11 slammed into the North Tower of the WTC, but with no radar return on the aircraft, no one in the FAA or NORAD were aware of the flight’s fate.

During this time the second flight – UA175 – had been hijacked while in New York ARTCC airspace. Both UA175 and AA11 had been in the same airspace, and as such both were being handled by the same controller. The controller’s priority was locating AA11 and as a result he failed to notice UA175’s transponder code change twice at 0846.

It wasn’t until 0851 that the controller noticed UA175’s transponder code had changed. This, like the initial signs from AA11, was not unusual – pilots entered the assigned beacon code manually and were known to make mistakes. The controller asked UA175 to recycle their beacon code, and returned his attention to locating AA11.

Events unfolded rapidly in the ensuing few minutes. The first news reports of an incident at the World Trade Centre began being broadcast, with major news networks interrupting their scheduled viewing. As with any major incident, initial reports were confused. The initial reports were of a light aircraft colliding with the WTC.

Over the next few minutes both NEADS and the FAA ATCSCC became aware of the news reports and started monitoring them. It was immediately apparent that the enormous gaping hole in WTC1 had been caused by something substantially larger than a light aircraft. NEADS contacted New York ARTCC to confirm the incident and discovered to their surprise that New York ARTCC was oblivious to it.

Communication began to break down as the system became overloaded with incidents. When Boston ARTCC tried to contact New York ARTCC, the controllers there said they were too busy with a hijacking to discuss the situation. The New York controllers were actually referring to the second hijacking, but Boston were unaware of a second hijacking, and assumed they were dealing with the hijacking of AA11.

UA175 meanwhile began to mirror AA11’s flight path, and turned towards New York. New York ARTCC’s repeated attempts to establish communication with UA175 were met with silence.

NEADS immediately suspected that AA11 had hit the WTC, and they had to decide what to do with their fighters which had just become airborne. If AA11 had crashed they were not needed and could return to base. However if the incident at the WTC was unrelated, AA11 was still airborne somewhere. NEADS decided to play it safe, and directed the Otis fighters to a holding position just off Lower New York Bay, about 10 miles south of JFK airport. There they would be close enough to be immediately utilized if it turned out AA11 was still airborne.

Meanwhile, far to the west over Kentucky, the third aircraft – American Airlines Flight 77 – was hijacked. At 0854 the aircraft deviated slightly from its flight path, then at 0856 the aircraft vanished. The Air Traffic Controller at Indianapolis ARTCC turned on their primary radar coverage but still the aircraft didn’t appear. Unknown to the controller – the radar data processor was only feeding them AA77’s return from a radar site that did not have primary radar. Without a transponder, the aircraft was invisible. When the controller tried to contact the flight they received nothing.

New York ARTCC, meanwhile, had concluded from repeated communication failures, that UA175 was hijacked. They notified the chain of command in accordance with protocol.

With two incidents in motion, and phone calls from flight crews reporting hijackings, American Airlines grounded every aircraft in their fleet in the north east of the country. United Airlines, meanwhile, faced with an unfolding incident on one of their aircraft, initiated a crisis centre to deal with the situation.

AA77, invisible to Indianapolis ARTCC’s radar, turned east, and began to descend. The air traffic controller continued in vain to locate the aircraft along its projected flight path to the west.


6.2 The Realization
Then at 0903 two simultaneous events occurred that totally changed the situation. Boston ARTCC had received several suspicious transmissions from the hijackers on board AA11 at 0824. Technicians at the centre had retrieved the recordings and had been searching through them to determine exactly what the hijackers had said. Now, 39 minutes later, they had uncovered a disturbing piece of information.

We have some planes.

Not plane. Planes. Plural. The FAA were facing multiple hijackings.

The ATCSCC had known this two minutes earlier when New York ARTCC reported the second hijacking, but this new piece of information revealed that the hijackings was part of a single coordinated incident.

At the same time New York ARTCC notified NEADS that they had a second hijacking incident in their airspace. Now both the FAA and NORAD knew multiple hijackings were underway.

But the second event to occur at 0903 would disrupt the air defense systems response in a much greater way.

At 0903, broadcast live on television around the world, UA175 was flown deliberately into the South Tower of the WTC, erupting into a fireball of red and yellow.

There was clearly nothing accidental about the impact, and it was clearly a Boeing 767, not a light aircraft. These two pieces of information together; multiple hijackings and a deliberate crash, changed everything. They changed the world.

Once it was clear what the air defense system was facing, it was immediately obvious that a different approach was needed – not just to the incident aircraft but to the entire air traffic network. The transmission from AA11 only said that there were multiple aircraft, it didn’t establish how many. Two? Four? Ten?

However, while in hindsight it is clear that 0903 was the definitive moment at which the nature of the attack changed, the realization for the air defense system came more slowly, and staggered.

At 0903:

The FAA ATCSCC knew there were two related hijackings, and they knew UA175 had been deliberately crashed. The fate of AA11 was unknown.

Boston ARTCC knew there was one hijacking, that another airliner had hit the WTC, and that AA11 was hijacked, and had probably also hit the WTC.

NEADS knew that there were two hijackings, that an airliner had deliberately hit the WTC, and that one of the hijackings – AA11 – had probably been the first aircraft to hit the WTC.

Indianapolis ARTCC knew that an aircraft had disappeared.

American Airlines knew that AA11 had been hijacked, and that it had crashed in the New York area at the time that WTC1 was hit, but they had gone into lockdown to protect details of the flight, and had not notified anyone of the fate of AA11. They also knew that another of their aircraft – AA77 – was still airborne and not responding to communication. They also had not passed this on to anyone else.

United Airlines knew that one of their flights had been hijacked and had crashed. They notified the FAA that UA175 had hit WTC2 within a few minutes.

The scope of information available to each element of the air defense system was sufficient to draw a conclusion regarding what was unfolding, but no element had all of the information at that time. As a result each element responded differently, and some responses interfered with others.

These differing responses resulted in the most confusing stage of the attack, and virtually paralyzed the air defense system.


6.2.1 The FAA ATCSCC
The FAA’s central command centre first knew of a hijacking at 0828, and learned of the incident at WTC1 within minutes of impact. From the news broadcasts they quickly determined that the impact had been caused by a large aircraft, which raised the possibility that it had been AA11.

At 0901 they learned of a second hijacking incident, and at 0903 they witnessed the impact of UA175. By 0905 the ATCSCC knew of the “we have some planes” transmission. They began communicating the situation to ATC centres in the region, and this information would reach Indianapolis ARTCC at about 0920 at which point they determined that AA77 was a possibly hijacking as well. Indianapolis ARTCC immediately notified the ATCSCC of this third hijacking incident. At 0925 the ATCSCC would further respond by ordering a nationwide ground stop which prevented any aircraft in the United States from taking off. At 0931 the ATCSCC ordered all field facilities to report anything out of the ordinary to them, no matter how minor. This order resulted in Cleveland ARTCC immediately notifying the ATCSCC that United Airlines Flight 93 had been hijacked.

The ATCSCC’s increased interest in unusual air traffic behaviour resulted in positive outcomes – they learned of AA77 and UA93 more quickly – however it also resulted in confusion as any aircraft failing to respond was immediately added to a list of hijackings until such time as its status was confirmed. Vital assets were diverted to chasing these false hijackings – for example NEADS expended valuable time trying to acquire fighter aircraft to intercept Delta Airlines Flight 1989, an aircraft which was not hijacked.


6.2.2 The ARTCCs
Several ARTCCs were directly involved in events by 0903. Boston ARTCC had handled the first hijacking and initiated communication with NEADS. For the period of the attacks the communication between NEADS and Boston ARTCC would be the only consistent bridge of communication between the FAA and the military. The reason for this was the FAA’s protocol which required a time consuming chain of authorization before a military request could be made. FAA headquarters would not begin discussing the scramble of fighter aircraft until ten minutes before the attacks ended.

Boston ARTCC not only provided NEADS with vital information about AA11, but would prove to be their only source of information for a number of incidents occurring outside Boston airspace. The Military Liaison at Boston ARTCC took on themselves the task of monitoring the FAA teleconferences and reporting any pertinent information to NEADS. This person became, by sheer happenstance, the lynchpin upon which the entire air defense response relied.

Boston ARTCC would also make an early decision to stop all departures in their airspace, following this with a declaration of ATC Zero – an order which closes the airspace to all air traffic.

New York Centre, meanwhile, made a number of decisions which hampered the air defense efforts, although their decision, in isolation, were sensible. Firstly, when UA175 was initially hijacked New York ARTCC handled the incident as any ordinary hijacking would be handled, and passed information up the chain of command to the FAA’s ATCSCC. New York Centre did not notify NEADS or Boston ARTCC of the hijacking, despite both control centres contacting New York about the other hijacking in progress.

At 0905, moments after the crash of UA175, New York declared ATC Zero and closed their airspace. However at the same time the fighters from Otis approached the border of New York airspace on their way to their holding point. With ATC Zero declared, New York refused the fighters entry, and directed them to Warning Area 105 – a military training area that begins 90 miles from the WTC.

It would be another twenty minutes before the fighters from Otis would finally be able to establish a presence over Manhattan. Both of these decisions by New York ARTCC resulted in delays to the air defense response.

Indianapolis ARTCC were handling AA77 when it was hijacked between 0851 and 0854. Circumstance meant that AA77 was hijacked in a sort box area assigned to one of Indianapolis ARTCC’s three beacon-only radar feeds and as such the aircraft could not be located on primary radar. With a loss of both radar and communication, Indianapolis ARTCC concluded the aircraft had suffered some sort of mid air break up. The centres beyond the immediate area of the hijackings had not been notified of what was happening, and thus Indianapolis ARTCC were oblivious to the other hijackings that were underway, and in particular the loss of communication that occurred with UA175 and the disabling of transponder that occurred with AA11.

Indianapolis proceeded to treat AA77 as an air disaster and initiated search and rescue procedures through the National Search and Rescue Coordination Centre at Langley Air Force Base. It would not be until 0920, when outlying ARTCCs learned of the hijackings, that anyone in the FAA would begin to reconsider AA77s fate, and by this time the aircraft had turned around and was only 17 minutes from the Pentagon. By this time AA77 was in Washington’s airspace, and neither Indianapolis ARTCC nor the FAA’s ATCSCC passed their suspicions on to Washington.

NEADS only reliable channel of information was Boston ARTCC, and so NORAD were not notified that AA77 was missing. It was not until 0934, when NEADS were contacting Washington ARTCC about AA11, that the Operations Manager at Washington ARTCC offhandedly mentioned that AA77 was missing as well. They did not mention that AA77 was a suspected hijacking because at the time Washington ARTCC didn’t know that both Indianapolis ARTCC and the ATCSCC were regarding AA77 as a hijacking.


6.2.3 The Airlines
Perhaps most interesting about 9/11 is that the affected airlines – American and United, both had more information and sooner about their flights than either the FAA or NORAD. The role of the airlines in the air defense response is often overlooked by both supporters of the official account and skeptics of the official account. Their role is vital, however, to understanding that day. Or perhaps more accurately, their lack of role was vital.

The airlines gained information through two distinct channels. The first is through their own monitoring systems. Both airlines operate their own Operations Centre which monitors and communicates with their entire fleet in real time. This allows the airlines to track their aircraft independent of the FAA.

In addition, the airlines received information in a way that neither the FAA or NORAD was able to receive it – directly from those on board the aircraft. American Airlines knew of a hijacking on AA11 from flight attendant Betty Ong five minutes after it occurred and five minutes before the FAA first suspected a hijacking had occurred. In this call Betty Ong would report that flight attendants and a passenger had been stabbed and that hijackers had seized control of the cockpit. Ong and another flight attendant – Madeline Sweeny, would later report that AA11 was in a rapid descent and flying erratically.

Despite this direct eyewitness information, American Airlines would not pass it on to the FAA or military, instead contacting the FAA seeking additional information. The airline would not regard the aircraft as a hijacking until after Boston ARTCC told them that they suspected it was a hijacking – despite a flight attendant on the aircraft having reported a hijacking 14 minutes earlier. Likewise when a flight attendant reported that the aircraft was in rapid descent they requested confirmation from air traffic controllers – despite the fact that air traffic controllers at the time were desperately trying to find any information about the aircraft’s altitude.

At 0836 American Airlines initiated “lock out” on AA11. This is a standard procedure which prevents any information on the aircraft being released to protect the identity of the flight and both passengers and crew. However this lock out prevented vital information from being relayed to the FAA – most notably a confirmation after 0846 that AA11 had crashed. American Airlines would ultimately not confirm the fate of AA11 until 45 minutes after it had crashed.

A similar pattern occurred with UA175. About ten minutes after the hijacking the airline knew via a male flight attendant that the aircraft was hijacked, that both pilots had been killed, and that the hijackers were flying the aircraft. This information was never passed on, however, as UA175 had the shortest flight time between hijacking at impact – it would crash only 9 minutes after the call from the flight attendant ended.

United Airlines would not begin “lock out” procedures for UA175 until 1921 – 18 minutes after it had crashed. However unlike American Airlines, United Airlines quickly confirmed that UA175 had hit the WTC.

American Airlines responded more quickly to the incident with AA77 than with AA11. They received word that ATC had lost contact with AA77 before 9am, and lock out was initiated for AA77 at 0905. American Airlines would cause confusion however as from 0908 some American Airlines officials were reporting that AA77 had been the second aircraft to hit the WTC. When a relative of a flight attendant on AA77 rang American Airlines to report the hijacking they initially thought they were referring to an aircraft that had hit the WTC, and the relative had to reiterate that AA77 was still airborne.

Again, American Airlines would be slow to confirm the fate of AA77 – it would be almost an hour after the aircraft had crashed before the airline confirmed it had crashed into the Pentagon.

Finally, United Airlines received a phone call from a flight attendant on board UA93 at 0936 – 8 minutes after the hijacking had occurred – to report what was happening on board the aircraft. By now the system had started to adjust to the new type of threat, and at 0940 United Airlines reported to the FAA that there was a problem with UA93. This call was the only example of an airline proactively seeking to inform the FAA of the situation on board one of their aircraft, however the FAA’s ATCSCC had learned of the incident with UA93 eight minutes earlier.

When United Airlines attempted to initiate lock out for UA93 at about 0950 they found they were unable to as the airline’s computer system was only designed to allow one lock out at a time, and United had already initiated lock out for UA175. Within ten minutes of UA93 crashing, United Airlines had confirmed the fate of the aircraft.


6.2.4 The Military
The central and most vital element in the air defense response was the NEADS command centre, but they were often the most poorly informed of what was occurring. Because FAA Headquarters failed to make an official request for military service no official line of communication was established between the US military and the FAA until well after the attacks had ceased. Independent attempts by the US military to establish official lines of communication with the FAA failed due to technical problems.

NEADS relied instead on mixed reports from a variety of ARTCCs. Of these, only Boston ARTCC made a serious attempt to provide NEADS with continual information, and NEADS received much of their information from other centres entirely by accident.

Despite this, NEADS were the first facility to grasp the seriousness of the situation, and begin reacting outside existing protocols. At 0903 NEADS knew that AA11 was hijacked, they knew that an unknown aircraft had hit WTC1 and had received reports of a second hijacking simultaneous with news broadcasts of an airliner flying into WTC2.

NEADS decided to assume the worst – that AA11 was not the first aircraft to hit the WTC and that more attacks would come. In the minutes after 0903 they were already adjusting to a new threat and began positioning tanker aircraft in the military training areas off the east coast in order to support their fighters. At 0919 NEADS were already discussing ways to shoot down an airliner – almost an hour before anyone in the chain of command actually thinks to authorize such action.


6.3 Rewriting The System
Within minutes of the first unquestionable sign that a new threat had appeared, the US military were ready to respond outside of protocol. However with this realization coming slowly to other facilities, and the military relying on intelligence from those facilities, the military were powerless to do anything. And as the situation progressed the ratio of noise to good intelligence only increased. When good intelligence was received, it was often received too late to do anything. NEADS were not told that AA77 was missing until three minutes before it crashed, and even then they were not told it was a suspected hijacking, nor where it was headed as the person telling them knew neither of those things. NEADS would not learn that UA93 had been hijacked until a full four minutes after it had crashed.

The attack was simply unfolding too rapidly for the system to adjust. By the time anyone in the system knew a coordinated suicide attack was underway, the attack was already half over – two of the aircraft had already crashed. This left only two opportunities for the system to rewrite itself.

But AA77 had vanished completely from radar, and no one knew where it was. The controllers that had been handling it were oblivious of the other hijackings for the first half hour in which they were looking for the flight. Once they had learned what was unfolding AA77 had long disappeared from their area of responsibility. Controllers in Washington ARTCC were looking for AA77 while it crossed their airspace, but they were unaware that AA77’s status had been altered to that of a suspected hijacking, and with no idea of the aircraft’s heading or altitude locating it was virtually impossible anyway.

AA77 finally was located on radar by Dulles TRACON only five minutes before it crashed. But no one knew that the aircraft being tracked over Washington DC was AA77, and there wasn’t any time to do anything about it anyway. Boston ARTCC informed NEADS of the radar return at 0936, but this was only a minute before the aircraft crashed, and the military had no fighters remotely near the radar return. The system had adjusted too slowly, and had been unable to stop AA77.

That left only one opportunity for the system to function as it was supposed to – United 93. UA93 was late in departing due to a backlog of morning traffic. Had the flight departed at its scheduled time it probably would have been hijacked at about the same time as UA175 and AA11, and would have reached its target long before the system had a chance to react.

By the time UA93 was hijacked at 0928 most of the system had adjusted to the new situation. ARTCC facilities across the country knew of the unfolding events on the east coast, and had been told to report any unusual activity to the ATCSCC. As soon as Cleveland ARTCC knew that UA93 had been hijacked they notified the ATCSCC, and the ATCSCC notified FAA Headquarters two minutes later.

As UA93 turned east Cleveland ARTCC were already asking the ATCSCC if anyone had notified the military. However at this point a crucial mix up appears to have occurred. Another aircraft in the same airspace as UA93, with the same flight profile, was Delta Airlines Flight 1989. Somehow these two flights became confused, and reports began to emerge on the FAA teleconference that DA89 had a bomb on board, when in fact a bomb had been reported on UA93. Boston ARTCC passed on the information about DA89 to NEADS at 0940. This was 12 minutes after UA93 was hijacked at only 8 minutes after the ARTCC suspected the aircraft was hijacked. Had the correct flight been identified, this would have been the most rapid notification to the military that occurred on 9/11.

NEADS would spend the next hour focusing on DA89 – effort that should have been directed at UA93. Meanwhile, however, the rest of the system began to regard UA93 differently to all other flights. At about the same time that NEADS were notified of DA89, the USSS had ordered fighters from the 121st Fighter Squadron at Andrews Air Force Base to establish a CAP over Washington DC. At the same time the 121st FS were told that Washington DC was a “free fire zone” – authorizing the use of force against any aircraft failing to comply with fighter pilot directions. By 0953 the FAA Headquarters were discussing a request for military fighters to intercept UA93. FAA Headquarters would not discuss a military scramble for any of the other flights.

Shortly after 1000 the executive issued orders to NORAD that they were authorized to shoot down any errant airliners. This directive was general in nature, but issued specifically in reference to knowledge that UA93 was approaching Washington DC.

By 1023, when it is estimated UA93 would have reached Washington DC, armed fighter aircraft are flying CAP over the capital, aware that UA93 is approaching and with authorization to shoot it down. The system was finally working.

However the system would never be called upon to execute these new hastily created protocols – while the system was realizing the nature of the threat so were the passengers onboard UA93. The same departure delay that gave the system time to prepare to counter UA93 also gave the passengers time to contact their loved ones and learn what had happened in Washington DC and New York. This small group of strangers were able to do what the system could not do – quickly disseminate information to all parties and quickly determine the best course of action. At 0957 the passengers on board UA93 stormed the cockpit in an attempt to retake control from the hijackers. After failing to stop the attack, the hijackers deliberately crashed the aircraft into a field in Pennsylvania. The passengers had achieved what the system had failed to do – they had prevented an attack.


Feedback, comments, corrections, or additional information welcome. Comments on content only please, not grammar or language - that comes later.

[cow_cat]

Gumboot,

Very nice work. It really helps to get a sense of the confusion that the people had to deal with. Above all, it also showed how quickly, not slowly, the agencies and people adapted to a copmletely new type of attack and even prevented one of them. I had no idea that the fighters over DC knew of an approaching plane and had authority to shoot it down.*

A couple of minor points.

1. "United Airlines would not begin “lock out” procedures for UA175 until 1921" - should be 0921?

2. Even though this is an extract, I think it would help to include a glossary of abbreviations and acronyms. ATCSCC, ARTCC, TRACON, NORAD and CAP could be confusing to a casual reader. YMMV.;)

Thanks for the article though, a definite bookmark for me.

[gumboot]

Gumboot,

Very nice work. It really helps to get a sense of the confusion that the people had to deal with. Above all, it also showed how quickly, not slowly, the agencies and people adapted to a copmletely new type of attack and even prevented one of them. I had no idea that the fighters over DC knew of an approaching plane and had authority to shoot it down.*

A couple of minor points.

1. "United Airlines would not begin “lock out” procedures for UA175 until 1921" - should be 0921?

2. Even though this is an extract, I think it would help to include a glossary of abbreviations and acronyms. ATCSCC, ARTCC, TRACON, NORAD and CAP could be confusing to a casual reader. YMMV.;)

Thanks for the article though, a definite bookmark for me.


Thanks for your feedback. The finished document will include a comprehensive glossary of terms, and the full name appears the first time it is used. For now I'll compile a quick glossary for this post. :)

The most significant aspect of the air defense failure was, in my opinion, a lack of communication. I think the biggest problem was that all four incidents (and all of the false incidents) were treated separately, and primary responsibility for dealing with them was left with whatever facility first dealt with the incident. There was no real centralised point at which the crisis was macro-managed, and through which data was passed.

This wasn't even a matter of problems between agencies - if we look just at American Airlines itself different sections of the company were "officially" saying conflicting things at various times. If the different organisations involved cannot even centralise their information, how can you hope to centralise information between organisations?

[gumboot]

Glossary of terms:

AADM Active Air Defense Mission
ADIZ Air Defense Identification Zone
AFB Air Force Base
AFIO Authorization For Interceptor Operations
ANG Air National Guard
ANGB Air National Guard Base
ANR Alaska NORAD Region
ARSR Air Route Surveillance Radar
ARTCC Air Route Traffic Control Center
ASR Airport Surveillance Radar
ATC Air Traffic Control/Controller
ATCBI Air Traffic Control Beacon Interrogator
ATCRBS Air Traffic Control Radar Beacon System
ATCSCC Air Traffic Control System Command Center
ATCT Airport Traffic Control Tower
ATF Advanced Tactical Fighter
AWACS Airborne Warning And Control System
BTH Beyond The Horizon
CANR Canada NORAD Region
CAP Combat Air Patrol
CDT Central Daylight Time
CFB Canada Forces Base
CJCS Chairman of the Joint Chiefs of Staff
CJCSI Chairman of the Joint Chiefs of Staff Instruction
CONR Continental USA NORAD Region
CPX Command Post Exercise
DEFCON Defense Condition
DOD Department of Defense
DODD Department of Defense Directive
EDT Eastern Daylight Time
EMERGCON Emergency Condition
FAA Federal Aviation Administration
FACSFAC Fleet Area Control and Surveillance Facility
FBI Federal Bureau of Investigation
FIX Field Exercise
FS Fighter Squadron
ft Foot/Feet
FW Fighter Wing
gal Gallon/s
IFF Identify Friend or Foe
JSS Joint Surveillance System
lb/s Pound/Pounds
MASCAL Mass Casualty
mi Mile/s
MPH Miles Per Hour
NCC NORAD Command Center
NDOC National Defense Operations Center
NEADS North East Air Defense Sector
NMCC National Military Command Center
nmi Nautical Mile/s
NORAD North American Aerospace Defense Command
NTSB National Transportation Safety Board
NWS North Warning System
PSR Primary Surveillance Radar
ROCC Region Operations Control Center
SCATANA Security Control of Air Traffic And Navigation Aids
SEADS South East Air Defense Sector
SOC System Operations Control
SOCC Sector Operations Control Center
SSR Secondary Surveillance Radar
TARS Tethered Aerostat Radar System
TRACON Terminal Radar Approach Control
UAV Unmanned Aerial Vehicle
US United States
USA United States of America
USAF United States Air Force
USSR Union of Soviet Socialist Republics
VACAPES Virginia Capes
WADS Western Air Defense Sector
WTC World Trade Center

[Travis]

I would suggest including the full procedure for requesting military support to a suspected hijacking. Basically expand on what you provided in paragraph 14 of section 6.1. This would show the immense amount of red tape that would normally have to be negotiated before anyone in any Air Defense Sector would be asked to do something about it. That, in turn, would show just how advantageous, if not ultimately successful, Boston Center's breaking of standard procedures was.

[Travis]

double post.

[Swing Dangler]

I've completed the first draft of the most important section of my paper, so I'm posting it here to get some more thorough feedback.

This is the "analysis" section where I look at the timeline of events in more detail and make some conclusions about how the system performed on 9/11.

PART SIX
ANALYSIS

The following section analyzes the events of 9/11 in more detail in order to draw some conclusions about how the air defense system functioned. I have divided this section into three broad categories that reflect three distinct stages of the day.

The first is the initial response to the attacks. This analyzes how well the existing systems worked in responding to initial reports of aircraft hijacking. This section covers up until 0903EDT.

The second section covers the system’s gradual realization that what was occurring was not a conventional hijacking but something wholly new; multiple coordinated suicide hijackings. The key moment was 0903EDT when UA175 was witnessed on television striking the South Tower of the WTC in what was quite clearly a deliberate act. However due to the compartmentalized nature of the air defense system the actual process of realization came at different times for different elements.

The final section analyzes how the system responded once it was clear they were dealing with a unique and unexpected threat. This is the period in which the air defense system had to improvise a new method for addressing the unfolding situation.

At all stages of this analysis I will attempt to make clear distinctions between what was actually occurring and what was known or believed by the various elements of the air defense system. Any defense system can only function in response to the intelligence it is receiving.


6.1 The Initial Response
The September 11 attacks began at 0814EDT. The daily rise in morning air traffic was beginning on the East Coast, and Air Traffic Controllers at Boston, New York and Washington ARTCCs were busy handling the increasingly busy skies above them. At 0814 an air traffic controller at Boston ARTCC experienced a momentary set back – one of the flights he was handling did not respond to communication. It was American Airlines Flight 11, a Boeing 767-223ER flying from Logan International Airport to Los Angeles International Airport.

Over a period of several minutes the controller made repeated attempts to reestablish communication with the aircraft. During the initial phase the controller would not have any reason to be concerned about AA11. Communication errors are not uncommon and are usually resolved in a matter of minutes. Typical causes include pilot inattention, interference, or incorrect use of equipment.

However as the minutes passed the situation would slowly begin to be considered more serious, with prolonged non-communication suggesting a radio failure on board the aircraft.

Seven minutes after loss of communication, the situation became more serious. At 0821 AA11’s transponder was turned off. Immediately, the data block attached to AA11’s radar return vanished, taking with it information such as the aircraft’s altitude, flight number, and beacon code.

The most likely cause of such an incident is some sort of power or system failure on board the aircraft. Activation of primary radar coverage can immediately establish that the aircraft is still airborne, ruling out some sort of catastrophic mid-air break up.

Three minutes later the situation again changed when Boston ARTCC received a series of three transmissions from AA11. The voice the controller heard was not the pilot, and appeared to have a middle-east accent. He appeared to be giving instructions to the passengers.

This is the first indication – at 0824 – that an incident has occurred on board AA11 and the pilots may no longer be in command of the aircraft. With the transponder deactivated, the FAA cannot receive the 7500 beacon code which would confirm a hijacking was underway.

At about the same time as the transmissions, AA11 deviated from its assigned flight path, and began a turn back towards New York City. This was in keeping with the transmission from the flight which stated the hijackers were returning the aircraft to the airport. A traditional hijacking is a hostage situation in which a group of people are held as a bargaining tool to gain specific objectives. The assumption is that a government will relent to the hijackers’ demands in order to secure the release of the hostages. An aircraft offers an attractive hijacking prospect as it is a completely contained environment. Thus the hijackers are able to execute the most vulnerable phase of their operation – seizure of the hostages – while confident that no one can interfere with them, and that hostages cannot escape. Due to the vulnerable nature of an aircraft in flight, air crews are trained to cooperate with hijackers and to make getting the aircraft on the ground their priority.

An aircraft hijacking will typically follow one of two paths – the first is that the hijackers will direct the aircraft to be landed at a specified airport where demands will be made of the authorities. The second is that the hijackers will direct the aircraft to be flown to a friendly state where they are seeking asylum.

The comments of the hijacker on AA11 and the flight path of the aircraft suggested the former scenario – the hijackers would instruct the pilots to fly the aircraft to an airport, land, and make demands of the US authorities in exchange for the release of hostages.

The presence of a hijacker in the cockpit, and the voice of a hijacker over the radio, were not in themselves signs of an irregular hijacking. Hijackers typically instruct pilots to follow their directions, and may do so with direct threat of violence. Hijackers may also wish to communicate with the passengers to ensure their cooperation, as appeared to be the case with AA11. The hijacker’s error in sending their comments through the radio rather than the aircraft’s PA could alternatively be an error on the hijacker’s part, or an act of subterfuge on the part of the aircrew, attempting to secretly alert the FAA to their situation. Initial media reports after 9/11 suggested this very scenario, until it became clear the hijackers had disabled the pilots immediately and piloted the aircraft themselves.

In the event of a typical hijacking the priority for Air Traffic Control is to ensure that the errant aircraft does not collide with other aircraft in the densely packed airspace. Sterilising airspace along the aircraft’s route is standard procedure, and Boston ARTCC immediately began doing this. In addition likely destination airports were alerted so that they too could sterilize their facilities in anticipation of the aircraft’s arrival.

Boston ARTCC began notifying the chain of command that AA11 was a suspected hijacking headed into New York immediately after the suspicious transmissions were received. The FAA’s ATCSCC in Herndon received word of the incident at 0828 and they in turn notified FAA Headquarters at 0832.

At this stage, 18 minutes into the hijacking, the only indication that the situation was anything other than a typical hijacking was the deactivation of the aircraft’s transponder. Without this Boston ARTCC could not determine AA11’s altitude. Based on this single discrepancy, Boston decided to deviate from normal protocol. In a typical hijacking the decision to involve a military escort would be made at FAA Headquarters and passed to the NMCC. Instead, Boston ARTCC contacted Cape TRACON at Falmouth, Massachusetts and asked them to request a fighter escort from the alert fighters at Otis Air National Guard Base.

This request was received at 0834. The call was received by the Massachusetts Air National Guard Director of Operations – Lieutenant Colonel Timothy Duffy. That day he was an assigned alert pilot with the 102nd Fighter Wing and would therefore be one of the pilots responding to the request. It was not normal to receive a scramble request directly from the FAA – normal protocol was for a scramble order to be received from NORAD. The situation required further investigation, however if a scramble was authorisied he would need to be ready for it. Duffy therefore transferred the call through to the Squadron Commander on duty that day. The other pilot on duty that day was Major Daniel Nash and he was assigned lead pilot. However the pilots decided together than Duffy would take the lead as he had previous experience escorting a hijacked aircraft in February 1993 when a Lufthansa flight was hijacked over the Mediterranean and diverted to JFK Airport in New York.

Meanwhile Boston ARTCC’s military liaison had arrived at the Operations Floor and immediately contacted NORAD’s North East Air Defense Sector to request a fighter scramble and to see if NEADS could establish the aircraft’s altitude. This call came at 0837.

Despite these unorthodox scramble requests, the military acted immediately and the Mission Crew Commander – Major Kevin Nasypany was immediately paged to the Operations Floor at NEADS.

The Squadron Commander at Otis contacted NEADS shortly afterwards and NEADS were able to confirm that they had received word of the hijacking and were working on it. It was at about this time that Duffy appeared at the Otis control tower to notify the Squadron Commander that he and Nash had decided to switch roles for this incident if they were scrambled. The Squadron Commander and Duffy both agreed that the two pilots should make their way to their aircraft on the assumption that they would be scrambled.

As soon as Nasypany arrived at the NEADS Ops Floor he ordered the Otis fighters to battle stations. This directs the pilots to climb into their aircraft and be on standby to take off. Because of the anticipation from the personnel at Otis, Nash and Duffy were already half way to their aircraft when the battle stations order was received.

At the same time Boston ARTCC were trying to determine AA11’s altitude, and to do this were asking nearby aircraft to be on the look out. The pilots of one particular aircraft – United Airlines Flight 175 – reported that they saw AA11 at an altitude of about 28,000 or 29,000ft. Boston ARTCC directed UA175 to change course to avoid AA11. At this time AA11 began a rapid descent towards the ground, however Boston ARTCC did not know this at the time as they did not have altitude data from the flight.

As AA11 descended the Tracking Technicians at NEADS desperately tried to find the aircraft amidst the dense noise of ground clutter along the eastern seaboard. With their radar sensitivity maximized to detect infiltrators at low altitude over the ocean, the landward sectors of their radar were an indecipherable storm of primary radar returns. One of them was their target aircraft.

At 0840 AA11 passed into New York ARTCC airspace, as did UA175. Immediately the military were on the back foot as the centre they were communicating with was no longer handling the aircraft.

Then at 0842 AA11 dropped below primary radar coverage and vanished from radar scopes. Controllers at Boston and New York and Tracking Techs at NEADS desperately tried to find the aircraft. With no confirmed radar returns, and with the aircraft in some of the most dense air traffic in the world, it became imperative that fighter aircraft intercepted the airliner to provide vital information on its location.

At 0844 NEADS decided that they didn’t have time to wait for an official scramble order, nor for the flight to be located on their radars. The MCC ordered the fighters from Otis to scramble to the aircraft’s last known position. From there the fighters would, through a process of elimination, cross reference every single radar return until they found the airliner. The fighters – with their own powerful radars and the pilot’s situation awareness – would have a much easier task than the Tracking Techs.

The scramble order was received by Otis ANGB at 0846. At that moment AA11 slammed into the North Tower of the WTC, but with no radar return on the aircraft, no one in the FAA or NORAD were aware of the flight’s fate.

During this time the second flight – UA175 – had been hijacked while in New York ARTCC airspace. Both UA175 and AA11 had been in the same airspace, and as such both were being handled by the same controller. The controller’s priority was locating AA11 and as a result he failed to notice UA175’s transponder code change twice at 0846.

It wasn’t until 0851 that the controller noticed UA175’s transponder code had changed. This, like the initial signs from AA11, was not unusual – pilots entered the assigned beacon code manually and were known to make mistakes. The controller asked UA175 to recycle their beacon code, and returned his attention to locating AA11.

Events unfolded rapidly in the ensuing few minutes. The first news reports of an incident at the World Trade Centre began being broadcast, with major news networks interrupting their scheduled viewing. As with any major incident, initial reports were confused. The initial reports were of a light aircraft colliding with the WTC.

Over the next few minutes both NEADS and the FAA ATCSCC became aware of the news reports and started monitoring them. It was immediately apparent that the enormous gaping hole in WTC1 had been caused by something substantially larger than a light aircraft. NEADS contacted New York ARTCC to confirm the incident and discovered to their surprise that New York ARTCC was oblivious to it.

Communication began to break down as the system became overloaded with incidents. When Boston ARTCC tried to contact New York ARTCC, the controllers there said they were too busy with a hijacking to discuss the situation. The New York controllers were actually referring to the second hijacking, but Boston were unaware of a second hijacking, and assumed they were dealing with the hijacking of AA11.

UA175 meanwhile began to mirror AA11’s flight path, and turned towards New York. New York ARTCC’s repeated attempts to establish communication with UA175 were met with silence.

NEADS immediately suspected that AA11 had hit the WTC, and they had to decide what to do with their fighters which had just become airborne. If AA11 had crashed they were not needed and could return to base. However if the incident at the WTC was unrelated, AA11 was still airborne somewhere. NEADS decided to play it safe, and directed the Otis fighters to a holding position just off Lower New York Bay, about 10 miles south of JFK airport. There they would be close enough to be immediately utilized if it turned out AA11 was still airborne.

Meanwhile, far to the west over Kentucky, the third aircraft – American Airlines Flight 77 – was hijacked. At 0854 the aircraft deviated slightly from its flight path, then at 0856 the aircraft vanished. The Air Traffic Controller at Indianapolis ARTCC turned on their primary radar coverage but still the aircraft didn’t appear. Unknown to the controller – the radar data processor was only feeding them AA77’s return from a radar site that did not have primary radar. Without a transponder, the aircraft was invisible. When the controller tried to contact the flight they received nothing.

New York ARTCC, meanwhile, had concluded from repeated communication failures, that UA175 was hijacked. They notified the chain of command in accordance with protocol.

With two incidents in motion, and phone calls from flight crews reporting hijackings, American Airlines grounded every aircraft in their fleet in the north east of the country. United Airlines, meanwhile, faced with an unfolding incident on one of their aircraft, initiated a crisis centre to deal with the situation.

AA77, invisible to Indianapolis ARTCC’s radar, turned east, and began to descend. The air traffic controller continued in vain to locate the aircraft along its projected flight path to the west.


6.2 The Realization
Then at 0903 two simultaneous events occurred that totally changed the situation. Boston ARTCC had received several suspicious transmissions from the hijackers on board AA11 at 0824. Technicians at the centre had retrieved the recordings and had been searching through them to determine exactly what the hijackers had said. Now, 39 minutes later, they had uncovered a disturbing piece of information.

We have some planes.

Not plane. Planes. Plural. The FAA were facing multiple hijackings.

The ATCSCC had known this two minutes earlier when New York ARTCC reported the second hijacking, but this new piece of information revealed that the hijackings was part of a single coordinated incident.

At the same time New York ARTCC notified NEADS that they had a second hijacking incident in their airspace. Now both the FAA and NORAD knew multiple hijackings were underway.

But the second event to occur at 0903 would disrupt the air defense systems response in a much greater way.

At 0903, broadcast live on television around the world, UA175 was flown deliberately into the South Tower of the WTC, erupting into a fireball of red and yellow.

There was clearly nothing accidental about the impact, and it was clearly a Boeing 767, not a light aircraft. These two pieces of information together; multiple hijackings and a deliberate crash, changed everything. They changed the world.

Once it was clear what the air defense system was facing, it was immediately obvious that a different approach was needed – not just to the incident aircraft but to the entire air traffic network. The transmission from AA11 only said that there were multiple aircraft, it didn’t establish how many. Two? Four? Ten?

However, while in hindsight it is clear that 0903 was the definitive moment at which the nature of the attack changed, the realization for the air defense system came more slowly, and staggered.

At 0903:

The FAA ATCSCC knew there were two related hijackings, and they knew UA175 had been deliberately crashed. The fate of AA11 was unknown.

Boston ARTCC knew there was one hijacking, that another airliner had hit the WTC, and that AA11 was hijacked, and had probably also hit the WTC.

NEADS knew that there were two hijackings, that an airliner had deliberately hit the WTC, and that one of the hijackings – AA11 – had probably been the first aircraft to hit the WTC.

Indianapolis ARTCC knew that an aircraft had disappeared.

American Airlines knew that AA11 had been hijacked, and that it had crashed in the New York area at the time that WTC1 was hit, but they had gone into lockdown to protect details of the flight, and had not notified anyone of the fate of AA11. They also knew that another of their aircraft – AA77 – was still airborne and not responding to communication. They also had not passed this on to anyone else.

United Airlines knew that one of their flights had been hijacked and had crashed. They notified the FAA that UA175 had hit WTC2 within a few minutes.

The scope of information available to each element of the air defense system was sufficient to draw a conclusion regarding what was unfolding, but no element had all of the information at that time. As a result each element responded differently, and some responses interfered with others.

These differing responses resulted in the most confusing stage of the attack, and virtually paralyzed the air defense system.


6.2.1 The FAA ATCSCC
The FAA’s central command centre first knew of a hijacking at 0828, and learned of the incident at WTC1 within minutes of impact. From the news broadcasts they quickly determined that the impact had been caused by a large aircraft, which raised the possibility that it had been AA11.

At 0901 they learned of a second hijacking incident, and at 0903 they witnessed the impact of UA175. By 0905 the ATCSCC knew of the “we have some planes” transmission. They began communicating the situation to ATC centres in the region, and this information would reach Indianapolis ARTCC at about 0920 at which point they determined that AA77 was a possibly hijacking as well. Indianapolis ARTCC immediately notified the ATCSCC of this third hijacking incident. At 0925 the ATCSCC would further respond by ordering a nationwide ground stop which prevented any aircraft in the United States from taking off. At 0931 the ATCSCC ordered all field facilities to report anything out of the ordinary to them, no matter how minor. This order resulted in Cleveland ARTCC immediately notifying the ATCSCC that United Airlines Flight 93 had been hijacked.

The ATCSCC’s increased interest in unusual air traffic behaviour resulted in positive outcomes – they learned of AA77 and UA93 more quickly – however it also resulted in confusion as any aircraft failing to respond was immediately added to a list of hijackings until such time as its status was confirmed. Vital assets were diverted to chasing these false hijackings – for example NEADS expended valuable time trying to acquire fighter aircraft to intercept Delta Airlines Flight 1989, an aircraft which was not hijacked.


6.2.2 The ARTCCs
Several ARTCCs were directly involved in events by 0903. Boston ARTCC had handled the first hijacking and initiated communication with NEADS. For the period of the attacks the communication between NEADS and Boston ARTCC would be the only consistent bridge of communication between the FAA and the military. The reason for this was the FAA’s protocol which required a time consuming chain of authorization before a military request could be made. FAA headquarters would not begin discussing the scramble of fighter aircraft until ten minutes before the attacks ended.

Boston ARTCC not only provided NEADS with vital information about AA11, but would prove to be their only source of information for a number of incidents occurring outside Boston airspace. The Military Liaison at Boston ARTCC took on themselves the task of monitoring the FAA teleconferences and reporting any pertinent information to NEADS. This person became, by sheer happenstance, the lynchpin upon which the entire air defense response relied.

Boston ARTCC would also make an early decision to stop all departures in their airspace, following this with a declaration of ATC Zero – an order which closes the airspace to all air traffic.

New York Centre, meanwhile, made a number of decisions which hampered the air defense efforts, although their decision, in isolation, were sensible. Firstly, when UA175 was initially hijacked New York ARTCC handled the incident as any ordinary hijacking would be handled, and passed information up the chain of command to the FAA’s ATCSCC. New York Centre did not notify NEADS or Boston ARTCC of the hijacking, despite both control centres contacting New York about the other hijacking in progress.

At 0905, moments after the crash of UA175, New York declared ATC Zero and closed their airspace. However at the same time the fighters from Otis approached the border of New York airspace on their way to their holding point. With ATC Zero declared, New York refused the fighters entry, and directed them to Warning Area 105 – a military training area that begins 90 miles from the WTC.

It would be another twenty minutes before the fighters from Otis would finally be able to establish a presence over Manhattan. Both of these decisions by New York ARTCC resulted in delays to the air defense response.

Indianapolis ARTCC were handling AA77 when it was hijacked between 0851 and 0854. Circumstance meant that AA77 was hijacked in a sort box area assigned to one of Indianapolis ARTCC’s three beacon-only radar feeds and as such the aircraft could not be located on primary radar. With a loss of both radar and communication, Indianapolis ARTCC concluded the aircraft had suffered some sort of mid air break up. The centres beyond the immediate area of the hijackings had not been notified of what was happening, and thus Indianapolis ARTCC were oblivious to the other hijackings that were underway, and in particular the loss of communication that occurred with UA175 and the disabling of transponder that occurred with AA11.

Indianapolis proceeded to treat AA77 as an air disaster and initiated search and rescue procedures through the National Search and Rescue Coordination Centre at Langley Air Force Base. It would not be until 0920, when outlying ARTCCs learned of the hijackings, that anyone in the FAA would begin to reconsider AA77s fate, and by this time the aircraft had turned around and was only 17 minutes from the Pentagon. By this time AA77 was in Washington’s airspace, and neither Indianapolis ARTCC nor the FAA’s ATCSCC passed their suspicions on to Washington.

NEADS only reliable channel of information was Boston ARTCC, and so NORAD were not notified that AA77 was missing. It was not until 0934, when NEADS were contacting Washington ARTCC about AA11, that the Operations Manager at Washington ARTCC offhandedly mentioned that AA77 was missing as well. They did not mention that AA77 was a suspected hijacking because at the time Washington ARTCC didn’t know that both Indianapolis ARTCC and the ATCSCC were regarding AA77 as a hijacking.


6.2.3 The Airlines
Perhaps most interesting about 9/11 is that the affected airlines – American and United, both had more information and sooner about their flights than either the FAA or NORAD. The role of the airlines in the air defense response is often overlooked by both supporters of the official account and skeptics of the official account. Their role is vital, however, to understanding that day. Or perhaps more accurately, their lack of role was vital.

The airlines gained information through two distinct channels. The first is through their own monitoring systems. Both airlines operate their own Operations Centre which monitors and communicates with their entire fleet in real time. This allows the airlines to track their aircraft independent of the FAA.

In addition, the airlines received information in a way that neither the FAA or NORAD was able to receive it – directly from those on board the aircraft. American Airlines knew of a hijacking on AA11 from flight attendant Betty Ong five minutes after it occurred and five minutes before the FAA first suspected a hijacking had occurred. In this call Betty Ong would report that flight attendants and a passenger had been stabbed and that hijackers had seized control of the cockpit. Ong and another flight attendant – Madeline Sweeny, would later report that AA11 was in a rapid descent and flying erratically.

Despite this direct eyewitness information, American Airlines would not pass it on to the FAA or military, instead contacting the FAA seeking additional information. The airline would not regard the aircraft as a hijacking until after Boston ARTCC told them that they suspected it was a hijacking – despite a flight attendant on the aircraft having reported a hijacking 14 minutes earlier. Likewise when a flight attendant reported that the aircraft was in rapid descent they requested confirmation from air traffic controllers – despite the fact that air traffic controllers at the time were desperately trying to find any information about the aircraft’s altitude.

At 0836 American Airlines initiated “lock out” on AA11. This is a standard procedure which prevents any information on the aircraft being released to protect the identity of the flight and both passengers and crew. However this lock out prevented vital information from being relayed to the FAA – most notably a confirmation after 0846 that AA11 had crashed. American Airlines would ultimately not confirm the fate of AA11 until 45 minutes after it had crashed.

A similar pattern occurred with UA175. About ten minutes after the hijacking the airline knew via a male flight attendant that the aircraft was hijacked, that both pilots had been killed, and that the hijackers were flying the aircraft. This information was never passed on, however, as UA175 had the shortest flight time between hijacking at impact – it would crash only 9 minutes after the call from the flight attendant ended.

United Airlines would not begin “lock out” procedures for UA175 until 1921 – 18 minutes after it had crashed. However unlike American Airlines, United Airlines quickly confirmed that UA175 had hit the WTC.

American Airlines responded more quickly to the incident with AA77 than with AA11. They received word that ATC had lost contact with AA77 before 9am, and lock out was initiated for AA77 at 0905. American Airlines would cause confusion however as from 0908 some American Airlines officials were reporting that AA77 had been the second aircraft to hit the WTC. When a relative of a flight attendant on AA77 rang American Airlines to report the hijacking they initially thought they were referring to an aircraft that had hit the WTC, and the relative had to reiterate that AA77 was still airborne.

Again, American Airlines would be slow to confirm the fate of AA77 – it would be almost an hour after the aircraft had crashed before the airline confirmed it had crashed into the Pentagon.

Finally, United Airlines received a phone call from a flight attendant on board UA93 at 0936 – 8 minutes after the hijacking had occurred – to report what was happening on board the aircraft. By now the system had started to adjust to the new type of threat, and at 0940 United Airlines reported to the FAA that there was a problem with UA93. This call was the only example of an airline proactively seeking to inform the FAA of the situation on board one of their aircraft, however the FAA’s ATCSCC had learned of the incident with UA93 eight minutes earlier.

When United Airlines attempted to initiate lock out for UA93 at about 0950 they found they were unable to as the airline’s computer system was only designed to allow one lock out at a time, and United had already initiated lock out for UA175. Within ten minutes of UA93 crashing, United Airlines had confirmed the fate of the aircraft.


6.2.4 The Military
The central and most vital element in the air defense response was the NEADS command centre, but they were often the most poorly informed of what was occurring. Because FAA Headquarters failed to make an official request for military service no official line of communication was established between the US military and the FAA until well after the attacks had ceased. Independent attempts by the US military to establish official lines of communication with the FAA failed due to technical problems.

NEADS relied instead on mixed reports from a variety of ARTCCs. Of these, only Boston ARTCC made a serious attempt to provide NEADS with continual information, and NEADS received much of their information from other centres entirely by accident.

Despite this, NEADS were the first facility to grasp the seriousness of the situation, and begin reacting outside existing protocols. At 0903 NEADS knew that AA11 was hijacked, they knew that an unknown aircraft had hit WTC1 and had received reports of a second hijacking simultaneous with news broadcasts of an airliner flying into WTC2.

NEADS decided to assume the worst – that AA11 was not the first aircraft to hit the WTC and that more attacks would come. In the minutes after 0903 they were already adjusting to a new threat and began positioning tanker aircraft in the military training areas off the east coast in order to support their fighters. At 0919 NEADS were already discussing ways to shoot down an airliner – almost an hour before anyone in the chain of command actually thinks to authorize such action.


6.3 Rewriting The System
Within minutes of the first unquestionable sign that a new threat had appeared, the US military were ready to respond outside of protocol. However with this realization coming slowly to other facilities, and the military relying on intelligence from those facilities, the military were powerless to do anything. And as the situation progressed the ratio of noise to good intelligence only increased. When good intelligence was received, it was often received too late to do anything. NEADS were not told that AA77 was missing until three minutes before it crashed, and even then they were not told it was a suspected hijacking, nor where it was headed as the person telling them knew neither of those things. NEADS would not learn that UA93 had been hijacked until a full four minutes after it had crashed.

The attack was simply unfolding too rapidly for the system to adjust. By the time anyone in the system knew a coordinated suicide attack was underway, the attack was already half over – two of the aircraft had already crashed. This left only two opportunities for the system to rewrite itself.

But AA77 had vanished completely from radar, and no one knew where it was. The controllers that had been handling it were oblivious of the other hijackings for the first half hour in which they were looking for the flight. Once they had learned what was unfolding AA77 had long disappeared from their area of responsibility. Controllers in Washington ARTCC were looking for AA77 while it crossed their airspace, but they were unaware that AA77’s status had been altered to that of a suspected hijacking, and with no idea of the aircraft’s heading or altitude locating it was virtually impossible anyway.

AA77 finally was located on radar by Dulles TRACON only five minutes before it crashed. But no one knew that the aircraft being tracked over Washington DC was AA77, and there wasn’t any time to do anything about it anyway. Boston ARTCC informed NEADS of the radar return at 0936, but this was only a minute before the aircraft crashed, and the military had no fighters remotely near the radar return. The system had adjusted too slowly, and had been unable to stop AA77.

That left only one opportunity for the system to function as it was supposed to – United 93. UA93 was late in departing due to a backlog of morning traffic. Had the flight departed at its scheduled time it probably would have been hijacked at about the same time as UA175 and AA11, and would have reached its target long before the system had a chance to react.

By the time UA93 was hijacked at 0928 most of the system had adjusted to the new situation. ARTCC facilities across the country knew of the unfolding events on the east coast, and had been told to report any unusual activity to the ATCSCC. As soon as Cleveland ARTCC knew that UA93 had been hijacked they notified the ATCSCC, and the ATCSCC notified FAA Headquarters two minutes later.

As UA93 turned east Cleveland ARTCC were already asking the ATCSCC if anyone had notified the military. However at this point a crucial mix up appears to have occurred. Another aircraft in the same airspace as UA93, with the same flight profile, was Delta Airlines Flight 1989. Somehow these two flights became confused, and reports began to emerge on the FAA teleconference that DA89 had a bomb on board, when in fact a bomb had been reported on UA93. Boston ARTCC passed on the information about DA89 to NEADS at 0940. This was 12 minutes after UA93 was hijacked at only 8 minutes after the ARTCC suspected the aircraft was hijacked. Had the correct flight been identified, this would have been the most rapid notification to the military that occurred on 9/11.

NEADS would spend the next hour focusing on DA89 – effort that should have been directed at UA93. Meanwhile, however, the rest of the system began to regard UA93 differently to all other flights. At about the same time that NEADS were notified of DA89, the USSS had ordered fighters from the 121st Fighter Squadron at Andrews Air Force Base to establish a CAP over Washington DC. At the same time the 121st FS were told that Washington DC was a “free fire zone” – authorizing the use of force against any aircraft failing to comply with fighter pilot directions. By 0953 the FAA Headquarters were discussing a request for military fighters to intercept UA93. FAA Headquarters would not discuss a military scramble for any of the other flights.

Shortly after 1000 the executive issued orders to NORAD that they were authorized to shoot down any errant airliners. This directive was general in nature, but issued specifically in reference to knowledge that UA93 was approaching Washington DC.

By 1023, when it is estimated UA93 would have reached Washington DC, armed fighter aircraft are flying CAP over the capital, aware that UA93 is approaching and with authorization to shoot it down. The system was finally working.

However the system would never be called upon to execute these new hastily created protocols – while the system was realizing the nature of the threat so were the passengers onboard UA93. The same departure delay that gave the system time to prepare to counter UA93 also gave the passengers time to contact their loved ones and learn what had happened in Washington DC and New York. This small group of strangers were able to do what the system could not do – quickly disseminate information to all parties and quickly determine the best course of action. At 0957 the passengers on board UA93 stormed the cockpit in an attempt to retake control from the hijackers. After failing to stop the attack, the hijackers deliberately crashed the aircraft into a field in Pennsylvania. The passengers had achieved what the system had failed to do – they had prevented an attack.


Feedback, comments, corrections, or additional information welcome. Comments on content only please, not grammar or language - that comes later.

Sources please?

[boloboffin]

I'll bet that Gumboot has all of that sourced in his paper, Swing. This is here for general comments. Since most people here see him as a valuable researcher and have seen evidence of his work before, we can wait to see the sourcing.

You can hide and watch if that's your only objection.

Of course, feel free to prove anything wrong in a single statement Gumboot has made.

[gumboot]

I would suggest including the full procedure for requesting military support to a suspected hijacking. Basically expand on what you provided in paragraph 14 of section 6.1. This would show the immense amount of red tape that would normally have to be negotiated before anyone in any Air Defense Sector would be asked to do something about it. That, in turn, would show just how advantageous, if not ultimately successful, Boston Center's breaking of standard procedures was.


Part Two of the paper deals with how the system is designed to operate. 2.1 outlines the peace time responsibilities of NORAD and the FAA, 2.2 specifically outlines aircraft piracy procedures, and 2.3 deals with Active Air Defense Missions and Air Defense Emergencies.

:)

[gumboot]

I'll bet that Gumboot has all of that sourced in his paper, Swing. This is here for general comments. Since most people here see him as a valuable researcher and have seen evidence of his work before, we can wait to see the sourcing.

You can hide and watch if that's your only objection.

Of course, feel free to prove anything wrong in a single statement Gumboot has made.


Quite right. This is a first draft of only one section of the paper. The completed paper will include a comprehensive reference list.

This particular section is an analysis of the timeline I have constructed.

The major resources used for the timeline are the 9/11 Commission's summary of the four flights, and the NEADS tapes. This has been supplemented with a variety of other resources such as news articles and trial exhibits.

[PhantomWolf]

At 0957 the passengers on board UA93 stormed the cockpit in an attempt to retake control from the hijackers. After failing to stop the attack, the hijackers deliberately crashed the aircraft into a field in Pennsylvania.

If I an recalling right, the CRV of 93 showed that they never actually breached the cockpit. Perhaps this sentence would be a little more accurate if you wrote something like:

At 0957 the passengers on board UA93 attempted to storm the cockpit in an effort to retake control from the hijackers. Realising that they would unable to prevent the passangers gaining entry, the hijackers deliberately crashed the aircraft into a field in Pennsylvania.

[boloboffin]

If I an recalling right, the CRV of 93 showed that they never actually breached the cockpit. Perhaps this sentence would be a little more accurate if you wrote something like:

At 0957 the passengers on board UA93 attempted to storm the cockpit in an effort to retake control from the hijackers. Realising that they would unable to prevent the passangers gaining entry, the hijackers deliberately crashed the aircraft into a field in Pennsylvania.

The family members who actually heard the CVR think that the passengers entered the cockpit, according to Among The Heroes. After comparing the transcript to the FDR, I agree with them. There is a moment when all evasive maneuvering of the plane stops. It's short, but it's there. And then comes an plunge from which the plane never recovers. It is as if Jarrah allows the passengers to finally break through the door before taking the plane down, a twist of the knife in the wound.