The FAA’s Boston Center calls the FAA Command Center and says it believes Flight 11 has been hijacked and is heading toward the New York Center’s airspace. The Command Center immediately establishes a teleconference between the Boston, New York, and Cleveland air traffic control centers, so Boston can help the other centers understand what is happening, in case Flight 11 should enter their airspace. Minutes later, in line with the standard hijacking protocol, the Command Center will pass on word of the suspected hijacking to the FAA’s Washington headquarters (see 8:32 a.m. September 11, 2001). [9/11 Commission, 7/24/2004, pp. 19; 9/11 Commission, 8/26/2004, pp. 11; Spencer, 2008, pp. 21]
National Operations Manager Learns of Hijacking – A supervisor at the Command Center promptly passes on the news of the possible hijacking to Ben Sliney, who is on his first day as the national operations manager there. The supervisor says the plane in question is “American Flight 11—a 767 out of Boston for Los Angeles.” According to author Lynn Spencer, “Sliney flashes back to the routine for dealing with hijackings from the days when they were more common.” The procedure is to “[k]eep other aircraft away from the errant plane. Give the pilots what they need. The plane will land somewhere, passengers will be traded for fuel, and difficult negotiations with authorities will begin. The incident should resolve itself peacefully, although the ones in the Middle East, he recalls, often had a more violent outcome.” Apparently not expecting anything worse to happen, Sliney continues to the conference room for the daily 8:30 staff meeting there (see 8:30 a.m.-8:40 a.m. September 11, 2001).
Command Center a ‘Communications Powerhouse’ – The FAA Command Center is located in Herndon, Virginia, 25 miles from Washington, DC. According to Spencer, it “is a communications powerhouse, modeled after NASA’s Mission Control. The operations floor is 50 feet wide and 120 feet long, packed with tiered rows of computer stations, and at the front, seven enormous display screens show flight trajectories and weather patterns.” The center has nearly 50 specialists working around the clock, planning and monitoring the flow of air traffic over the United States. These specialists work with airlines and air traffic control facilities to fix congestion problems and deal with weather systems. [Spencer, 2008, pp. 1 and 19-20]
8:45 a.m. September 11, 2001: Air Traffic Control Centers Receive False Bomb Threats
CNN will report that, while Flight 11 is heading toward the World Trade Center, “[S]ources say there were bomb threats called in to air traffic control centers adding to the chaos.” One center receiving such threats is the FAA’s Boston Center, which handles air traffic over New England and monitors flights 11 and 175. The FAA’s Cleveland Center, which will monitor Flight 93, receives similar threats (see 10:07 a.m.-10:21 a.m. September 11, 2001). Whether other centers are threatened is unstated. According to Newsweek, “Officials suspect that the bomb threats were intended to add to the chaos, distracting controllers from tracking the hijacked planes.” [Newsweek, 9/22/2001; CNN, 9/30/2001] Yet, just weeks after 9/11, the Washington Post will claim: “Federal aviation officials no longer believe that accomplices of the hijackers made phony bomb threats to confuse air traffic controllers on September 11. Sources said reports of multiple threats were apparently the result of confusion during the early hours of the investigation and miscommunication in the Federal Aviation Administration.” [Washington Post, 9/27/2001]
Shortly After 9:03 a.m. September 11, 2001: FBI Calls FAA’s Cleveland Center, Warns It to Watch Delta 1989
Shortly after the second attack on the World Trade Center, FBI agents call the FAA’s Cleveland Center and warn air traffic controllers there to keep an eye on Delta Air Lines Flight 1989. According to USA Today, controllers at the Cleveland Center, which is tracking Delta 1989, have already been watching this flight, and, like the FBI, suspect “that terrorists plan to hijack [it] next.” Although Delta 1989 is not showing any signs of being hijacked, the reason for their suspicion is that it has many similarities to the two aircraft that hit the World Trade Center: it is also a Boeing 767, heavy with fuel, and had taken off from Boston’s Logan Airport around the same time as they did. [USA Today, 8/13/2002] At 9:27 a.m., the FAA’s Boston Center will—apparently mistakenly—report that Delta 1989 is missing (see 9:27 a.m. September 11, 2001). [9/11 Commission, 5/23/2003] And at around 9:30 a.m., Cleveland Center controllers will mistakenly conclude that it has been hijacked (see (9:28 a.m.-9:33 a.m.) September 11, 2001). [USA Today, 8/13/2002]
9:19 a.m. September 11, 2001: FAA Concerned about Delta Flight 1989, Wants It to Increase Cockpit Security
The FAA’s New England regional office calls the FAA’s Herndon Command Center, and asks it to tell Cleveland Center to contact Delta Air Lines Flight 1989 and advise it to use extra cockpit security. The reason the New England regional office makes this request is unclear. [9/11 Commission, 7/24/2004, pp. 10] As the 9/11 Commission will describe, apparently in response to the request, “[A]t 9:19 the FAA… Command Center in Herndon ordered controllers to send a cockpit warning to Delta 1989 because, like American 11 and United 175, it was a transcontinental flight departing Boston’s Logan Airport.” [9/11 Commission, 7/24/2004, pp. 455] Minutes earlier, the FAA’s Boston Center asked the Command Center to contact the nation’s FAA centers and instruct them to tell all airborne aircraft to increase their cockpit security (see (9:15 a.m.) September 11, 2001). The Command Center’s instruction to air traffic controllers about Delta 1989 is apparently an exception, as the 9/11 Commission will say it found “no evidence to suggest that the Command Center acted on this request.” [9/11 Commission, 7/24/2004, pp. 23; 9/11 Commission, 8/26/2004, pp. 25-26] Delta 1989 will subsequently be mistakenly reported as having been hijacked (see (9:28 a.m.-9:33 a.m.) September 11, 2001 and 9:39 a.m. September 11, 2001). [USA Today, 8/13/2002; Vanity Fair, 8/1/2006]
9:24 a.m.-9:25 a.m. September 11, 2001: Flight 93 Checks in with Cleveland Air Traffic Control, Mentions No Problems
Having entered the center’s airspace, Flight 93 establishes radio contact with the FAA’s Cleveland Center, a regional air traffic control center that guides long-range, high altitude flights. The pilot reports simply that his flight is experiencing intermittent light choppy air, and does not indicate there being any problems on board, saying, “Good morning Cleveland, United 93 with you at three-five-oh [35,000 feet], intermittent light chop.” The controller, John Werth, is busy with other flights, so does not initially respond. A minute later, Flight 93 radios again, “United 93 checking in three-five-oh.” Werth replies, “United 93, three-five-zero, roger.” [Gregor, 12/21/2001 
; Longman, 2002, pp. 69; 9/11 Commission, 8/26/2004, pp. 37; CBS News, 9/10/2006] Two minutes later, Flight 93 will make its final radio communication before the hijacker takeover occurs (see 9:27 a.m. September 11, 2001).
9:27 a.m. September 11, 2001: Flight 93 Makes Last Contact with Air Traffic Control
Flight 93 makes its last normal communication with air traffic control before being hijacked, acknowledging a routine radio transmission from the FAA’s Cleveland Center. [9/11 Commission, 7/24/2004, pp. 28] Flight 93 checked in with the Cleveland Center a couple of minutes earlier (see 9:24 a.m.-9:25 a.m. September 11, 2001). At 9:27, the Cleveland controller, John Werth, alerts it to another aircraft 12 miles away and to its right, at 37,000 feet: “United 93, that traffic for you is one o’clock, 12 miles east, bound three-seven-zero.” Seconds later, Flight 93 responds, “Negative contact, we’re looking, United 93.” Less than a minute after this, the hijackers appear to enter Flight 93’s cockpit (see (9:28 a.m.) September 11, 2001). [Gregor, 12/21/2001 ; Longman, 2002, pp. 69; CBS News, 9/10/2006]
9:28 a.m. or Before September 11, 2001: Erratic Flight 93 Movements Noticed by Cleveland Flight Controller
Cleveland flight controller Stacey Taylor has been warned to watch transcontinental flights heading west for anything suspicious. She later recalls, “I hear one of the controllers behind me go, ‘Oh, my God, oh my God,’ and he starts yelling for the supervisor. He goes, ‘What is this plane doing? What is this plane doing?’ I wasn’t that busy at the time, and I pulled it up on my screen and he was climbing and descending and climbing and descending, but very gradually. He’d go up 300 feet, he’d go down 300 feet. And it turned out to be United 93.” (Note the time of this incident is not specified, but presumably it is prior to when Cleveland controllers note Flight 93 descends 700 feet at 9:29 a.m. [MSNBC, 9/11/2002]
9:28 a.m. September 11, 2001: Cleveland Flight Control Hears Sounds of Struggle as Flight 93 Is Hijacked
According to the 9/11 Commission, less than a minute after Flight 93 acknowledged a routine radio transmission from the FAA’s Cleveland Center (see 9:27 a.m. September 11, 2001), John Werth—the controller handling the flight—and pilots of other aircraft in the vicinity of Flight 93 hear “a radio transmission of unintelligible sounds of possible screaming or a struggle from an unknown origin.” [Federal Aviation Administration, 9/11/2001; 9/11 Commission, 6/17/2004 ; CBS News, 9/10/2006] Someone, presumably Flight 93’s pilot Jason Dahl, is overheard by controllers as he shouts, “Mayday!” [New York Times, 7/22/2004] Seconds later, the controller responds, “Somebody call Cleveland?” Then there are more sounds of screaming and someone yelling, “Get out of here, get out of here.” [Toronto Sun, 9/16/2001; Newsweek, 9/22/2001; Observer, 12/2/2001; MSNBC, 7/30/2002; 9/11 Commission, 6/17/2004 ] Then the voices of the hijackers can be heard talking in Arabic. The words are later translated to show they are talking to each other, saying, “Everything is fine.” [Newsweek, 12/3/2001] Later, passenger phone calls will describe two dead or injured bodies just outside the cockpit; presumably these are the two pilots. [New York Times, 7/22/2004]
9:28 a.m.-9:33 a.m. September 11, 2001: Cleveland Center Controllers Mistakenly Think Delta 1989 Is Hijacked
The FAA’s Cleveland Center incorrectly concludes that Delta Air Lines Flight 1989 has been hijacked, but accounts will conflict over how it comes to this conclusion. [USA Today, 8/13/2002; Spencer, 2008, pp. 167] Delta 1989, a Boeing 767, is currently in the sector of airspace being monitored by Cleveland Center air traffic controller John Werth. [9/11 Commission, 10/2/2003 ; USA Today, 9/11/2008] It is flying west over Pennsylvania, approaching the Ohio border, and is about 25 miles behind Flight 93. FBI agents suspected Delta 1989 might be the next plane to be hijacked and called the Cleveland Center after the second attack on the World Trade Center, with the warning to watch this flight (see Shortly After 9:03 a.m. September 11, 2001). [USA Today, 8/13/2002] A supervisor at the center told Werth to keep an eye on the flight because, as Werth will later recall, “he was a suspected hijacking because he had taken off from Boston at approximately the same time as” the first two hijacked aircraft, Flights 11 and 175. [9/11 Commission, 10/1/2003 ; USA Today, 9/11/2008]
Controllers Hear Suspicious Communications – When, at 9:28, Werth hears the sound of screaming (subsequently determined to have come from Flight 93) over the radio (see (9:28 a.m.) September 11, 2001), he is unsure which of seven or eight possible aircraft it is coming from. The radio frequency is put on the speaker so other controllers can hear it, and they subsequently make out the words, “get out of here.” [9/11 Commission, 10/1/2003 ; 9/11 Commission, 7/24/2004, pp. 11, 28]
Controllers Think Delta 1989 Is Hijacked – According to USA Today, when Cleveland Center controllers then hear a voice with a heavy accent over the radio, saying “Ladies and gentlemen: Here the captain.… We have a bomb on board” (see (9:32 a.m.) September 11, 2001), they mistakenly think it is coming from Delta 1989, not Flight 93. They suspect the flight has been hijacked, and start informing their chain of command. “Officials at Cleveland Center rush word to Washington: Hijackers have another flight. At the Federal Aviation Administration’s Command Center in Herndon, Virginia, Delta Flight 1989 joins a growing list of suspicious jets.” [USA Today, 8/13/2002; 9/11 Commission, 7/24/2004, pp. 12]
Werth Decides Hijacked Aircraft Is Flight 93 – Werth then calls all of the aircraft in his sector, and Flight 93 is the only one that does not respond. He also sees Flight 93 go into a quick descent and then come back up again. Werth therefore concludes that it is Flight 93, not Delta 1989, that has been hijacked, and instructs his supervisor to “tell Washington” of this. [9/11 Commission, 10/1/2003 ; 9/11 Commission, 10/2/2003 ] However, events in the following minutes will cause Cleveland Center controllers to remain suspicious of Delta 1989 (see (Shortly After 9:44 a.m.) September 11, 2001 and 9:45 a.m. September 11, 2001). [USA Today, 8/13/2002; 9/11 Commission, 10/2/2003 ; Spencer, 2008, pp. 168; USA Today, 9/11/2008]
Book Gives Alternative Account – In a book published in 2008, author Lynn Spencer will give a different explanation for why Cleveland Center becomes suspicious of Delta 1989. According to her account, after hearing a later radio transmission where a hijacker again says “There is a bomb on board” (see (9:39 a.m.) September 11, 2001), Werth begins to hand off his flights to other controllers so he can devote his full attention to Flight 93. “In the distraction of the emergency, the crew of Delta 1989 misses the hand-off to the new frequency. The new sector controller for Delta 1989 calls out to the plane several times and gets no response.” As a result, “News travels fast,” and “Soon, word on the FAA’s open teleconference call is that a fifth aircraft is out of radio contact: Delta 1989… is added to the list of suspect aircraft.” [Spencer, 2008, pp. 167] At 9:39 a.m., even though it is not responsible for handling Delta 1989, the FAA’s Boston Center will call NORAD’s Northeast Air Defense Sector (NEADS) and incorrectly tell it that Delta 1989 is another possible hijack (see 9:39 a.m. September 11, 2001). [9/11 Commission, 2004; Vanity Fair, 8/1/2006]
Between 9:28 a.m. and 10:06 a.m. September 11, 2001: Executive Jet Tracks Flight 93
A small jet plane—ExecuJet 956—tracks Flight 93 for what is described as “a substantial period of time” before it crashes, and picks up some of the radio transmissions from it, as both planes are operating on the same frequency. [Government’s motion for protective order regarding cockpit voice recorder pursuant to 49 USC 1154. United States v. Zacarias Moussaoui, 8/8/2002 ; Washington Post, 8/9/2002] The exact period over which ExecuJet 956 follows Flight 93 is unclear. But as early as 9:31 it calls the FAA’s Cleveland Center and, referring to Flight 93, reports: “[W]e’re just answering your call. We did hear that, uh, yelling too.” [9/11 Commission, 7/24/2004, pp. 461] At 9:40, after being asked, “did you understand that transmission [from Flight 93]?” ExecuJet 956 tells Cleveland Center: “Affirmative. He said that there was a bomb on board.” [Associated Press, 4/12/2006] Cleveland Center then asks the ExecuJet pilot if he can change course and try to spot Flight 93. He sees it, loses it, and then sees it again. He then has to make an evasive turn, as Flight 93 is heading directly for him. [Longman, 2002, pp. 104] ExecuJet 956 is one of a fleet of small jets available for hire from a company based in Woodbridge, New Jersey called NetJets, which sells shares in private business aircraft. [Associated Press, 8/8/2002; Washington Post, 8/9/2002] NetJets’ owner is the multi-billionaire Warren Buffet. [Knight Ridder, 11/6/2001; Observer, 1/12/2003] Another small business jet is reportedly within 20 miles of Flight 93 when it crashes, but this is apparently a different one, belonging to a North Carolina clothing firm (see 10:07 a.m. September 11, 2001). [Pittsburgh Channel, 9/15/2001; Pittsburgh Post-Gazette, 9/16/2001]
