U.S. military response during the September 11 attacks



On September 11, 2001, hijackers flew three of four hijacked commercial airliners into three buildings in the United States without encountering military intervention. American Airlines Flight 11, departing from Boston, was flown into the North Tower of World Trade Center at 8:46 a.m. United Airlines Flight 175, also departing from Boston, was flown into the South Tower at 9:03. American Airlines Flight 77, departing from Washington, was flown into the Pentagon at 9:37. United Airlines Flight 93, departing from Newark, crashed near Shanksville, Pennsylvania at 10:03.

Standing orders on September 11 dictated that, upon receiving a request for assistance from the Federal Aviation Administration (FAA), the North American Aerospace Defense Command (NORAD) would normally order escort aircraft to approach and follow an aircraft that was confirmed to be hijacked in order to assure positive flight following, report unusual observances, and aid search and rescue in the event of an emergency. The 9/11 Commission determined that on the morning of September 11, the FAA did not notify NORAD of the hijackings of Flights 11, 175, 77 or 93 in time for escort aircraft to reach the hijacked flights.Notification of the hijacking of Flight 11 prompted the scrambling of two fighter jets from Otis Air National Guard Base, but they were not in the air until after Flight 11 had hit the North Tower. An erroneous FAA report of a hijacked plane heading towards Washington ("phantom Flight 11") prompted the scrambling of three more fighters from the 1st Fighter Wing at Langley Air Force Base, which due to poor communications, ended up flying eastward, out to sea, instead of heading toward Washington, significantly delaying their arrival on the scene.

Radar Tracking
On September 11, the radar systems used by the FAA in the areas along the flight paths of the four hijacked aircraft were a combination of the latest Air Route Surveillance Radar-4 (ARSR-4, areas near the coast) and earlier ARSR versions (areas further inland). The ARSR-4 system was developed jointly for the FAA and the USAF to replace earlier search and height-finder radars. ARSR radar systems work by detecting primary target data and merging it with data from a secondary beacon system onboard the aircraft, known as transponders, and then transmitted to FAA’s Air Route Traffic Control Centers (ARTCC's, usually referred to by pilots as "Centers") and Air Force Air Defense Sectors (NEADS/Rome, a JSS Region Operations Control Centre (ROCC)). The ARTCC's tracking the flights on 9/11 included Boston, New York, Washington, Cleveland, and Indianapolis.

The hijackers of the four planes switched off the transponders or changed their codes upon taking control, making it difficult to track them on radar. Northeast Air Defense Sector/NORAD personnel stated they had difficulty identifying and tracking the aircraft, though they were at times able to locate them:


 * NEADS technicians spotted American Airlines flight 11 twenty miles north of Manhattan, just two or three minutes before it crashed into the north tower of the World Trade Center.


 * “Looking at the general capitol area, one of the [NEADS] tracker techs thinks he spots the plane on radar.”


 * The 9/11 Commission Report: “Radar techs at NEADS/Rome are tracking Flight 77 near Washington, D.C.”

An Enhanced Traffic Management System (ETMS) hubsite, which generates and receives data to/from many remote sites, achieved full operation in September 1992. Designed to be ETMS-interactive, the Standard Terminal Automation Replacement System (STARS) began in the early 1990s as a jointly-procured parallel-developed program of FAA and the Dept. of Defense. STARS is a fully digital system capable of displaying all aircraft using FAA and DoD surveillance systems within their defined airspace.

Even with loss of transponder-based secondary radar returns, aircraft can usually be tracked with long range primary radar through the use of repetitive triangulation iterations via multiple radars at precisely known distances, as used in the Joint Surveillance System. Real-time locating via transponders requires less computation. Multilateration, the process of locating aircraft based on the time difference of arrival (TDOA) of its transponder signal to three or more strategically placed receiver stations, was developed decades ago for the military. Because multilateration data is updated every second, targets move at a much smoother and more accurate progression. However, as the transponders in three of the four hijacked aircraft were switched off, and the remaining aircraft had changed its transponder code twice, multilateration was of little use to the military for tracking the hijacked flights on 9/11, though the FAA, who had been monitoring the flights continuously since their departure, was able to track the planes at least some of the time after being hijacked. The FAA had difficulty relaying the current aircraft positions to NORAD/NEADS by phone, so even though they had access to the same radar data, NEADS was unable to locate most of the flights. This intermittent data was of some use to the US Secret Service. Barbara Riggs, then Deputy Director of the Secret Service stated, “Thru monitoring radar and activating an open line with the FAA, the Secret Service was able to receive real time information about other hijacked aircraft. We were tracking two hijacked aircraft as they approached Washington, D.C.”

Flight 11
At 8:14, the pilot of Flight 11 failed to respond to an instruction to ascend issued from Boston Center, the FAA's Air Traffic Control (ATC) center which controls the airspace. The pilot was, at that time, flying opposite Boston arrivals, and as Flight 11 began to pose an air hazard, air traffic controllers began to reroute arriving aircraft for adequate separation. Boston Center flight controller Tom Roberts said "We had pretty much moved all the airplanes from Albany, New York to Syracuse, New York out of the way because that’s the track he was going on.'" At 8:20 EDT, Betty Ong, an American Airlines flight attendant on Flight 11, called the American Airlines reservation desk to report the Flight as hijacked. After 08:21 EDT, American Airlines Flight 11 no longer transmitted transponder altitude or identification information.

After colliding with the World Trade Center, American Airlines officials did not confirm loss of Flight 11 for several hours.

At 8:21, the aircraft (now visible only on primary radar) began to veer radically off course. At 8:25, the controller heard what he believed was the voice of a hijacker in a radio transmission from Flight 11. The Boston Center called the FAA Command Center at Herndon at 8:28 to report the hijacking. At 8:32, Herndon called FAA Headquarters in Washington. At 8:34, Boston Center contacted Otis Air National Guard (ANG) base to notify them of the hijacking. The controller at Otis directed Boston to contact NORAD's Northeast Air Defense Sector (NEADS), and then informed the Otis Operations Center to expect a call from NEADS ordering a scramble. At this time two pilots began to suit up and drove to their waiting F-15 fighter jets. At 8:38, Boston Center contacted NEADS in Rome, New York. This was the first report of a hijacking that reached NORAD.

The two F-15 alert aircraft at Otis Air National Guard Base in Falmouth, Massachusetts were ordered to battle stations (seated in their aircraft, engines not yet started). At 8:46, just at the time the first tower was hit, Nash and Duffy were ordered to scramble (an order that begins with engine start-up, a process that takes about five minutes), and radar confirmed they were airborne by 8:53. By that time, however, the World Trade Center's North Tower had already been hit.

At that time, NEADS personnel were still trying to pinpoint the location of Flight 11, but were unable. Without having a specific target located, military commanders were uncertain where to send the fighters. Boston Center controllers were still tracking Flight 11 as a primary target but were unable to communicate its location to NEADS by phone. Colin Scoggins, the military liaison at the FAA’s Boston Center, later said "I was giving NEADS accurate location information on at least 5 instances where AA11 was yet they could never find them.  … I originally gave them an F/R/D, which is a fixed radial distance from a known location; they could not identify the target.  They requested latitudes/longitudes, which I gave them; they still could not identify AA11.  I gave them 20 south of Albany heading south at a high rate of speed, 600 knots, then another call at 50 south of Albany.”

After the news of an aircraft hitting the World Trade Center, no decision was made to alter the course of the F-15s of the 102nd Fighter Wing. A decision was made to send the Otis fighters south of Long Island rather than to just north of New York City, as originally ordered by Maj. Nasypany of NEADS.

One of the pilots, Lieutenant Colonel Timothy Duffy, would later state he had already heard about the suspected hijacking (attributed to a phone call from the FAA’s Boston Center) as he was supervising training exercises at Otis ANG base. Claiming to have a "bad feeling about the suspected hijacking", he and his wingman, Major Daniel Nash, decided to use their F-15’s afterburners.

Flying supersonicly, the F-15’s were just south of Long Island when United Airlines Flight 175 smashed into the World Trade Center’s south tower. NEADS wanted to direct the fighters over Manhattan, but FAA air controllers, fearing collisions with civilian aircraft, told NEADS to hold off. According to the FAA, there is an average of 200 flights per 24 hours over the Hudson River in the vicinity of NYC. The fighters were then ordered in a holding pattern off the coast of Long Island (in military-controlled airspace), where they remained from 9:09 to 9:13. After the airspace was cleared, the Otis fighters were directed towards Manhattan, where they arrived at 9:25 and established a Combat Air Patrol (CAP).

Colin Scoggins, aware that the 177th Fighter Wing launches F-16s for training flights every morning around this time from their base on Atlantic City International Airport, suggested to NORAD’s Northeast Air Defense Sector (NEADS) that it contact Atlantic City to use these jets in response to the hijacked Flight 11 out of concern that Otis fighters would be unable to intercept in time. Scoggins would later recount: “I requested that we take [off] from Atlantic City very early in the [morning], not launch from the ground but those already airborne in Warning Area 107 [a training area] if they were there, which I believe they were.” NEADS did not follow that request. Around this time, two F-16s from the 177th Fighter Wing were away from base performing a training mission, and were eight minutes flying time away from New York City in the Pine Barrens of New Jersey, closer than Otis by two minutes' flying time. The two fighter jets were unarmed and performing practice bombing runs over a section of the Pine Barrens in New Jersey that is designated for military drills. Pilots from the 177th routinely train for interception of hostile aircraft, and military pilots had anticipated having to use their unarmed planes as air-to-air missiles if unarmed. About an hour after the Sept. 11 attacks began, the 177th received orders to send up fully armed F-16s in response.

The 9/11 Commission report stated “The center tried to contact a former alert site in Atlantic City, unaware it had been phased out.”

Flight 175
At 8:41 at the New York en route center in Islip, Long Island, United Flight 175 entered controllers Dave Bottiglia and Curt Applegate's airspace. The aircraft's transponder was at that time transmitting the assigned code. Its last radio transmission was at 8:42. As Bottiglia and other controllers searched the radar, looking for American 11, he suddenly noticed that United Flight 175, which moments before helped him locate American 11, had changed its transponder code twice at 8:47. He asked another controller to take over all of his other planes.

Bottiglia tried six times to contact flight 175 between 8:51 and 8:55, with no response. The aircraft deviated from its assigned altitude at 8:51, and began its turn toward New York City at 8:52. At 8:55 Bottiglia told a manager at FAA New York Center that he thought Flight 175 had been hijacked. According to the 9/11 Commission report, this manager then "tried to contact regional managers but was told that they were discussing hijacked aircraft (presumably American 11) and refused to be disturbed." At around this time, United Flight 175 flew within about 200 feet of Delta Flight 2315, bound from Bradley to Tampa, Florida.

In the final moments before impact, according to eyewitness and Newark air traffic controller Rick Tepper, the plane executed ".. a hard right bank, diving very steeply and very fast. As he was coming up the Hudson River, he made another hard left turn..." One or two minutes before it crashed into the World Trade Center, Flight 175 narrowly avoided a mid-air collision with Midwest Airlines Flight 7 (Midex 7). At 9:01, a New York Center manager called FAA Command Center at Herndon. NEADS was notified at 9:03, when the New York Center manager called them directly, at about the time that Flight 175 hit the South Tower. The F-15s were still 71 miles away from Manhattan when United Airlines Flight 175 smashed into the WTC's south tower.

Although NORAD knew of no other hijacked aircraft, a precautionary measure was taken by ordering fighters at Langley Air Force Base to battle stations.

Phantom Flight 11
At 9:21, NEADS received another call from Colin Scoggins, who reported erroneously that Flight 11 was not, in fact, the aircraft that hit the North Tower at 8:46, as had been previously believed, but that it was still in the air and heading towards Washington. NEADS responded to this report by giving a scramble order to three fighters from the 1st Fighter Wing on alert at Langley Air Force Base at 9:24, and by 9:30 they were in the air. According to the 9/11 commission, the Langley pilots were never briefed by anyone at their base about why they were being scrambled, so, despite Langley officials' having been given the order from NEADS to fly to Washington, the unbriefed pilots ended up following their normal training flight plan, due east, out to sea. The fighters then flew north-west towards Washington, arriving around 10:00.

Flight 77
American Airlines Flight 77 took off from Dulles International Airport outside Washington D.C. at 8:20 AM. The flight proceeded normally until 8:55 AM, when the aircraft deviated from its assigned course by initiating a turn to the south. The transponder of Flight 77 was switched off at 8:56 AM, and its primary radar track was lost. Later, after hearing about the hijacked planes hitting the World Trade Center, Indianapolis Center suspected that Flight 77 may also have been hijacked, and shared this information with FAA Command Center at Herndon, where staff contacted FAA Headquarters in Washington at 9:25AM.

NEADS learned that the flight was lost at 9:34 during a phone call with the FAA Headquarters. 9:34:01 “Washington Center: Now let me tell you this. I – I’ll – we’ve been looking. We’re – also lost American 77 ... They lost contact with him. They lost everything. And they don’t have any idea where he is or what happened.” The FAA did not contact NEADS to make this report. This phone call was initiated by NEADS in an attempt to locate Phantom Flight 11 (see previous).

At 9:35, Colin Scoggins from the FAA's Boston Center again called NEADS to inform them that they had located an aircraft, which later turned out to be American Airlines flight 77, heading toward Washington DC at a high rate of speed. Two minutes later, a NEADS radar technician spotted a target he believed to be flight 77. This radar target was in fact flight 77 near Washington, DC, but the target vanished as soon as it was discovered. NEADS officials urgently ordered the fighters from Langley to be sent to Washington immediately, but flight 77 had already struck the Pentagon at 9:37:45. The Langley fighters were still 150 miles away.

Flight 93
At 9:28, FAA Cleveland Center controller John Werth heard "sounds of possible screaming" coming from Flight 93 and noticed that the plane had descended 700 feet, transponder turned off. At the time, Werth knew that some passenger jets were missing and that one had hit a World Trade Center tower in New York. At 9:32, he heard a voice saying "We have a bomb on board" and told his supervisor who then notified FAA Headquarters. At 9:36, FAA Cleveland called FAA Command Center at Herndon to ask whether the military had been notified - FAA Command Center told Cleveland that "FAA personnel well above them in the chain of command had to make the decision to seek military assistance and were working on the issue". At 9:49, the decision about whether to call the military had still not been made, and no one from the FAA did call them until 10:07, four minutes after Flight 93 had crashed near Shanksville, PA. Werth later commented: Within three or four minutes, probably, of when it happened, I asked if the military was advised yet. Had anybody called the military? They said, "don't worry, that's been taken care of," which I think to them meant they had called the command center in Washington."

Dennis Fritz, director of the municipal airport in Johnstown, Pa., said the FAA called him several times as the plane approached his city, and even warned him to evacuate the tower for fear the jet would crash into it.

NORAD timeline
On September 18, 2001, NORAD issued a press release containing a timeline of the events of the September 11, including when they were contacted by the FAA. This page has been removed, but a copy can be found at archive.org. However, in 2004, the 9/11 Commission, after listening to tapes of communications, found that this timeline was incorrect. The NORAD timeline had served as the official account of the military response, and appeared in the book Air War over America, and was given in testimony to the 9/11 Commission by NORAD's General Larry Arnold and Colonel Alan Scott in 2003.

The Washington Post reported in its August 3, 2006 edition that: "Some staff members and commissioners of the Sept. 11 panel concluded that the Pentagon's initial story of how it reacted to the 2001 terrorist attacks may have been part of a deliberate effort to mislead the commission and the public rather than a reflection of the fog of events on that day, according to sources involved in the debate.

Suspicion of wrongdoing ran so deep that the 10-member commission, in a secret meeting at the end of its tenure in summer 2004, debated referring the matter to the Justice Department for criminal investigation, according to several commission sources. Staff members and some commissioners thought that e-mails and other evidence provided enough probable cause to believe that military and aviation officials violated the law by making false statements to Congress and to the commission, hoping to hide the bungled response to the hijackings, these sources said."

In their 2007 book, Without Precedent, 9/11 Commission chairmen Thomas Kean and Lee Hamilton wrote that 9/11 conspiracy theories had grown primarily because of problems in the previous story about the planes: "If the military had had the amount of time they said they had... and had scrambled their jets, it was hard to figure out how they had failed to shoot down at least one of the planes... In this way, the FAA's and NORAD's inaccurate reporting after 9/11 created the opportunity for people to construct a series of conspiracy theories that persist to this day."

"The tapes recordings... from the day were extremely important - they provided a real-time record of what was happening that enabled our staff to relive the day, instead of relying solely on people's memory or their hurried notes of what took place."

The NORAD timeline showed that the FAA had notified NORAD earlier than the taped evidence indicated, and the 9/11 Commission Report faulted the FAA for not contacting NORAD quickly enough. The NORAD timeline showed notification of the hijacking of Flight 175 at 8:43, while the tapes show NORAD was notified after Flight 175 hit the South Tower at 9:03.

According to the 9/11 Commission report, at approximately 8:32 the FAA's Herndon Command Center established a teleconference between Boston, New York, and Cleveland Centers so that Boston Center could help the others understand what was happening. Controllers at the Boston Center knew American Airlines Flight 11, which departed at 7:59 a.m. ET from Boston for its flight to Los Angeles, was hijacked 30 minutes before it crashed. They tracked it to New York on their radar scopes. 'I watched the target of American 11 the whole way down,' said Boston controller Mark Hodgkins. Several Boston controllers tracked American 11 for its entire flight.

The FAA mistakenly thought Flight 11 was still possibly airborne, in part because American Airlines would not confirm for 2 hours that they had lost all contact with Flight 11. The NORAD timeline showed that the fighters scrambled from Langley at 9:24 were in response to a 9:21 FAA report of the hijacking of Flight 77; NORAD never mentioned phantom Flight 11.

United Airlines confirmed loss of Flight 175 within minutes to the FAA. A NORAD General and a Colonel testified that they were notified about the hijacking of Flight 93, and had fighters in position to shoot it down if necessary, and had received the order from Dick Cheney to do so, if necessary.

In October 2003, the 9/11 Commission issued a subpoena to the FAA to turn over documents after the Commission's investigators determined that material had been withheld. A tape was made of oral statements of New York air traffic controllers, intended to be used as an aid in their making written statements, then destroyed. A quality assurance manager at the FAA's New York Center denied the staff access to the tape and later destroyed it. Its existence came to light in 2003 interviews with FAA staff. The Commission subpoenaed the tape and other records from the FAA on Oct. 16, 2003. In November 2003, the Commission issued a subpoena to NORAD; its second subpoena issued to a federal agency for failure to turn over documents.

In July 2004, the 9/11 commission made referrals to the Inspectors General of both the US Department of Transportation and the Defense Department to further investigate whether witnesses had lied. Commission staff believes there is sufficient evidence that the false statements made to the commission were deliberately false. [John Farmer, Jr., the commission’s senior counsel] The DoD Inspector General's report was released to the New York Times in August 2006 under a FOIA request. According to the report, military officials were exonerated of intentionally misleading the 9/11 Commission in their testimony. A summary of the report called for more steps to improve the Defense Department's ability to investigate "a future significant air event," including more effective event logging methods

The US Transportation Department’s Inspector General’s investigation report was released on August 31, 2006. FAA personnel were also exonerated of knowingly misleading the 9/11 Commission.

Conspiracy theories
The response of the air defense system on the morning of September 11, 2001 is a commonly-discussed aspect of 9/11 "inside job" conspiracy theories. One claim is that evidence shows the military was under a "stand-down" order.

Background
In January 1982, the FAA unveiled the National Airspace System (NAS) Plan. The plan called for more advanced systems for Air Traffic Control, and improvements in ground-to-air surveillance and communication with new Doppler Radars and better transponders. Better computers and software were developed, air route traffic control centers were consolidated, and the number of flight service stations reduced. There is no overlap of responsibility between DoD and FAA within the NAS: this is why within FAA-controlled airspace the FAA is in charge of controlling and vectoring hijack intercept aircraft.

The radar systems at NEADS had been scheduled to be upgraded in a contract awarded in 1997, but the project cost had been revised upwards by 700% causing the Air Force to cancel the contract and begin plans to re-open the bidding process.

84th Squadron had planned on tracking transponder-less aircraft at some point prior to 9-11. Planning for terrorist use of hijacked airplanes as missiles had been considered for some military exercises prior to 9/11, though all but one of those exercises considered only aircraft originating from other countries.

The US and Canadian militaries, particularly NORAD and the US Air National Guard, have been tasked with interception duties concerning hijacked aircraft. Their primary duty was assistance to law enforcement. Quoting Maj.Gen. Larry Arnold: "We always viewed an attack from within our borders as a law enforcement issue, ...". Military aircraft were to be used to assure positive flight following, report unusual observances, and aid search and rescue in the event of an emergency. Jamie Gorelick of the 9-11 Commission had taken part in those security measures as Deputy Attorney General, and described the measures in Commission hearings. In April 2001, NORAD considered an exercise in which an aircraft of foreign origin was hijacked by terrorists and flown into the Pentagon, like a missile, but rejected the scenario as implausible. Five months later, a similar scenario occurred. However, in January 2002 Maj.Gen. Larry Arnold, stated "...we did not honestly think about hijacked airliners being used in suicide attacks."

Efforts post-9/11
In April 2003, a contract was awarded to upgrade the Battle Control Systems, operational date by summer 2006.

Later systems, such as the Joint-Based Expeditionary Connectivity Center (JBECC), merge civil and military radar data. Once deployed, the JBECC can fuse and correlate target data covering about 400 miles (640 km) of coastline from disparate airborne, land- and sea-based sensors creating fire-control-quality tracks that can guide interceptors to engagement.

Major General Larry Arnold, USAF, ret. stated in May, 2001, that JBECC will provide "... more time to scramble fighters and see any target, whether small, large, low or high."

General Arnold also stated "In the immediate aftermath of 9/11 we had to hook up to FAA radars throughout the country, install compatible radios for nationwide coverage between our command and control agencies and our airborne assets, and purchase a new command and control computer system to integrate radar and communications. The initial investment was for $75 million, and this number has grown to nearly $200 million."

Organizations outside the FAA (e.g., the airlines, Department of Defense, NASA, and international sites) also have access to the FAA's Enhanced Traffic Management System (ETMS) software and/or data for purposes of flight management and tracking.

2009 Government Accountability Office report on ASA
In January 2009, the Government Accountability Office (GAO) published "Homeland Defense: Actions Needed to Improve Management of Air Sovereignty Alert Operations to Protect U.S. Airspace" on the Air Force's Air Sovereignty Alert mission. According to the report: The Air Force has not implemented ASA operations in accordance with DOD, NORAD, and Air Force directives and guidance, which instruct the Air Force to establish ASA as a steady-state (ongoing and indefinite) mission. The Air Force has not implemented the 140 actions it identified to establish ASA as a steady-state mission, which included integrating ASA operations into the Air Force’s planning, programming, and funding cycle. The Air Force has instead been focused on other priorities, such as overseas military operations. While implementing ASA as a steady-state mission would not solve all of the challenges the units must address, it would help them mitigate some of the challenges associated with conducting both their ASA and warfighting missions. The report further stated: The GAO analysis also showed that none of the Air Force's key homeland defense documents—the Air Force homeland defense policy directive, the Air Force homeland operations doctrine, and the Air Force homeland defense concept of operations—fully defines the roles and responsibilities for, or accurately articulates the complexity of, Air Sovereignty Alert operations. The report made the following recommendations to improve ASA operations: We recommend that the Secretary of Defense direct the Commander of the U.S. command element of NORAD to routinely conduct risk assessments to determine ASA requirements, including the appropriate numbers of ASA sites, personnel, and aircraft to support ASA operations.

We recommend that the Secretary of Defense direct the military services with units that consistently conduct ASA operations to formally assign ASA duties to these units and then ensure that the readiness of these units is fully assessed, to include personnel, training, equipment, and ability to respond to an alert.

We recommend that the Secretary of Defense direct the Secretary of the Air Force to take the following five actions:
 * • Establish a timetable to implement ASA as a steady-state mission.
 * • Implement ASA as a steady-state mission according to NORAD, DOD, and Air Force guidance by
 * • updating and implementing the ASA program action directive;
 * • updating the Air Force homeland defense policy, homeland operations doctrine, and concept of operations to incorporate and define the roles and responsibilities for ASA operations; and
 * • incorporating the ASA mission within the Air Force submissions for the 6-year Future Years Defense Program.
 * • Develop and implement a plan to address any projected capability gaps in ASA units due to the expected end of the useful service lives of their F-15s and F-16s.
 * • Develop and implement a formal method to replace deploying units that still provides unit commanders flexibility to coordinate replacements.