U.S. military response during the September 11 attacks
On the morning of Tuesday, September 11, 2001, Islamist terrorist group al-Qaeda hijacked four commercial airliners in the United States and tried to crash them into large buildings, succeeding in three cases. American Airlines Flight 11, having departed from Boston, was flown into the North Tower of the World Trade Center at 08:46. United Airlines Flight 175, also leaving from Boston, struck the South Tower at 09:03. American Airlines Flight 77, from Washington Dulles International Airport, hit the Pentagon at 09:37. United Airlines Flight 93, from Newark Liberty International Airport, was crashed near Shanksville, Pennsylvania, at 10:03, after the passengers on board revolted.
Main article: September 11 attacksStanding orders on September 11 dictated that, on receiving a request for help 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 ensure positive flight following, report unusual observations, and help in search and rescue in an emergency.[1] The 9/11 Commission determined that, on the morning of September 11, the FAA had not notified NORAD of the hijackings of Flights 11, 77, 93, and 175 in time for escort aircraft to reach the hijacked flights.[2] 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 fighters from the 1st Fighter Wing at Langley Air Force Base, which, because of "poor communications", flew east, out to sea, not toward Washington, significantly delaying their arrival on the scene.[2]
On taking control of the airliners, the hijackers of the four planes switched off the transponders or changed their codes, making it difficult to track them on radar. Northeast Air Defense Sector (NEADS) / NORAD personnel stated they had trouble identifying and tracking the aircraft, succeeding only sometimes:
Because the transponders in three of the four hijacked aircraft were switched off, and the remaining aircraft had changed its transponder code twice, the FAA had difficulty relaying the current aircraft positions to NORAD/NEADS by phone: even though they had access to the same radar data, NEADS could not find most of the flights. The intermittent data were of some use to the United States Secret Service. Barbara Riggs, then deputy director of the Secret Service, stated, "Through 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."[5]
Flight 175[edit]
United Airlines Flight 175 departed Logan Airport at 08:14 also bound for Los Angeles just like Flight 11. At 08:42, when Flight 175's pilots sent their last radio transmission, the aircraft's transponder was at that time transmitting the assigned code. Five minutes later, the transponder code changed twice, the first indication that the plane had been hijacked, although air traffic controllers would not notice for several more minutes. As word began spreading about the hijacking of Flight 11, air traffic controller David Bottiglia and other controllers searched the radar, looking for Flight 11. At 08:51, he noticed that Flight 175 had changed its transponder.[6][24] He asked another controller to take over all of his other planes.[6]
Bottiglia tried six times to contact Flight 175 between 08:51 and 08:55, with no response.[24] The aircraft deviated from its assigned altitude at 08:51, and began its turn toward New York City at 08:52.[25] At 08:55, 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 Flight 11) and refused to be disturbed."[2] At around this time, Flight 175 flew within about 200 feet of Delta Air Lines Flight 2315, bound from Bradley to Tampa, Florida.
In the final moments before impact, according to eyewitness and Newark air traffic controller Rick Tepper, Flight 175 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 ..."[6] 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).[26] At 09:01, a New York Center manager called FAA Command Center at Herndon. NEADS was notified at 09:03, when the New York Center manager called them directly, at about the time that Flight 175 hit the South Tower.[2] The F-15s were still 20 minutes away from Manhattan when United Airlines Flight 175 impacted the WTC's south tower.[10]
Although NORAD knew of no other hijacked aircraft, a precautionary measure was taken by ordering fighters at Langley Air Force Base to battle stations.[2]
Phantom Flight 11[edit]
At 09:21, 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 08:46, 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 119th Fighter Wing on alert at Langley Air Force Base at 09:24, and by 9:30 they were in the air.[27] 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.[2]
Air Sovereignty Alert (ASA) preparedness[edit]
Background[edit]
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.[1]
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.[47]
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.[48]
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, ...".[49] 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.[1] 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.[48] Five months later, a similar scenario occurred.[50] However, in January 2002 Maj.Gen. Larry Arnold, stated "... we did not honestly think about hijacked airliners being used in suicide attacks."[49]
Efforts post-9/11[edit]
In April 2003, a contract was awarded to upgrade the Battle Control Systems by summer 2006.[51]
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."[52]
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."[26]
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.[53]
2009 Government Accountability Office report on ASA[edit]
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"[54] on the Air Force's Air Sovereignty Alert mission. According to the report:
The report further stated:
The report made the following recommendations to improve ASA operations: