!! History Commons Alert, Exciting News

Context of '(Between 8:13 a.m. and 8:21 a.m.) September 11, 2001: Flight 11 Transponder Turned Off'

This is a scalable context timeline. It contains events related to the event (Between 8:13 a.m. and 8:21 a.m.) September 11, 2001: Flight 11 Transponder Turned Off. You can narrow or broaden the context of this timeline by adjusting the zoom level. The lower the scale, the more relevant the items on average will be, while the higher the scale, the less relevant the items, on average, will be.

Shortly after air traffic controllers ask Flight 11 to climb to 35,000 feet, its transponder stops transmitting. A transponder is an electronic device that identifies a plane on a controller’s screen and gives its exact location and altitude. Among other vital functions, it is also used to transmit a four-digit emergency hijack code. Flight control manager Glenn Michael later says, “We considered it at that time to be a possible hijacking.” [Christian Science Monitor, 9/13/2001; MSNBC, 9/15/2001; Associated Press, 8/12/2002] Initial stories after 9/11 suggest the transponder is turned off around 8:13 a.m., but Pete Zalewski, the air traffic controller handling the flight, later says the transponder is turned off at 8:20 a.m. [MSNBC, 9/11/2002] The 9/11 Commission places it at 8:21 a.m. [9/11 Commission, 6/17/2004] Colonel Robert Marr, head of NEADS, claims the transponder is turned off some time after 8:30 a.m. where the Flight 11 hijack was first detected a.m. [ABC News, 9/11/2002]

Entity Tags: Pete Zalewski, Glenn Michael, Robert Marr

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

John Hartling.John Hartling. [Source: NBC News]By 8:34 a.m., Flight 11 has entered airspace managed by Boston Center air traffic controller John Hartling. [MSNBC, 9/11/2002; 9/11 Commission, 7/24/2004, pp. 19] Although Boston controller Pete Zalewski, who was managing Flight 11, concluded the plane was hijacked almost ten minutes earlier (see (8:25 a.m.) September 11, 2001), at the time the blip for Flight 11 appears on Hartling’s radar screen, Hartling is unaware that a hijacking is taking place. According to author Lynn Spencer, the reason is that “The concentration required for the job is so intense that controllers operate on a need-to-know basis. They don’t need to know what’s happening in other controllers’ sectors unless it might affect their own airspace, and distractions are rigorously kept to a minimum.” Tom Roberts, another Boston Center controller, has just been relieved from duty for a scheduled coffee break, and comes over to Hartling’s desk. Referring to Flight 11’s radar track, he tells Hartling, “This—this aircraft, we believe, is hijacked, and he’s last reported at 29,000 feet.” However, Hartling is incredulous. He will later recall that when Roberts says the plane is hijacked, “I didn’t believe him.” This is because “I didn’t think that that stuff would happen anymore, especially in this country.” Hartling continues tracking Flight 11 as it heads toward New York. Although its transponder has been turned off (see (Between 8:13 a.m. and 8:21 a.m.) September 11, 2001), he can tell that, at almost 600 mph, it is flying far faster than the 450 mph it should be moving at. [MSNBC, 9/11/2002; Spencer, 2008, pp. 22-24]

Entity Tags: Boston Air Route Traffic Control Center, John Hartling, Tom Roberts

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Tech. Sgt. Jeremy Powell.Tech. Sgt. Jeremy Powell. [Source: Scott A. Gwilt/ Rome Sentinel]The FAA’s Boston Center calls NORAD’s Northeast Air Defense Sector (NEADS) in Rome, NY, to alert it to the suspected hijacking of Flight 11. According to the 9/11 Commission, this is “the first notification received by the military—at any level—that American 11 had been hijacked.” [9/11 Commission, 7/24/2004, pp. 20; 9/11 Commission, 8/26/2004, pp. 13] The call is made by Joseph Cooper, an air traffic controller at the Boston Center, and answered by Jeremy Powell, a technical sergeant on the NEADS operations floor. [Vanity Fair, 8/1/2006; Spencer, 2008, pp. 25] Beginning the call, Cooper says: “Hi. Boston Center TMU [traffic management unit], we have a problem here. We have a hijacked aircraft headed towards New York, and we need you guys to, we need someone to scramble some F-16s or something up there, help us out.” Powell replies, “Is this real-world or exercise?” Cooper answers, “No, this is not an exercise, not a test.” [9/11 Commission, 7/24/2004, pp. 20] Shortly into the call, Powell passes the phone on to Lieutenant Colonel Dawne Deskins (see (8:38 a.m.) September 11, 2001). Deskins identifies herself to Cooper, and he tells her, “We have a hijacked aircraft and I need you to get some sort of fighters out here to help us out.” [Newhouse News Service, 1/25/2002; ABC News, 9/11/2002; Bamford, 2004, pp. 8; Spencer, 2008, pp. 26]
Military Claims Call Goes against Procedure - The 1st Air Force’s official history of the response to the 9/11 attacks will later suggest that Boston Center is not following normal procedures when it makes this call to NEADS. It states: “If normal procedures had taken place… Powell probably wouldn’t have taken that phone call. Normally, the FAA would have contacted officials at the Pentagon’s National Military Command Center who would have contacted the North American Aerospace Defense Command. The secretary of defense would have had to approve the use of military assets to assist in a hijacking, always considered a law enforcement issue.” The only explanation it gives for this departure from protocol is that “nothing was normal on Sept. 11, 2001, and many say the traditional chain of command went by the wayside to get the job done.” [Filson, 2003, pp. 51]
Accounts Conflict over Time of Call - There will be some conflict between different accounts, as to when this vital call from Boston Center to NEADS occurs. An ABC News documentary will indicate it is made as early as 8:31 a.m. [ABC News, 9/11/2002] Another ABC News report will state, “Shortly after 8:30 a.m., behind the scenes, word of a possible hijacking [reaches] various stations of NORAD.” [ABC News, 9/14/2002] NEADS logs indicate the call occurs at 8:40 a.m., and NORAD will report this as the time of the call in a press release on September 18, 2001. [Federal Aviation Administration, 9/17/2001 pdf file; North American Aerospace Defense Command, 9/18/2001] The 8:40 time will be widely reported in the media prior to the 9/11 Commission’s 2004 report. [Associated Press, 8/21/2002; BBC, 9/1/2002; Newsday, 9/10/2002; CNN, 9/11/2002] But tape recordings of the NEADS operations floor that are referred to in the 9/11 Commission Report place the call at 8:37 and 52 seconds. [9/11 Commission, 7/24/2004, pp. 20; Vanity Fair, 8/1/2006] If the 8:37 a.m. time is correct, this would mean that air traffic controllers have failed to successfully notify the military until approximately 12 minutes after they became certain that Flight 11 had been hijacked (see (8:25 a.m.) September 11, 2001), 16 minutes after Flight 11’s transponder signal was lost (see (Between 8:13 a.m. and 8:21 a.m.) September 11, 2001), and 24 minutes after the plane’s pilots made their last radio contact (see 8:13 a.m. September 11, 2001). [9/11 Commission, 6/17/2004] At 8:34, the Boston Center tried contacting the military through the FAA’s Cape Cod facility, which is located on Otis Air National Guard Base, but was told that it needed to call NEADS (see 8:34 a.m. September 11, 2001). [9/11 Commission, 7/24/2004, pp. 20; Spencer, 2008, pp. 22]

Entity Tags: Boston Air Route Traffic Control Center, Dawne Deskins, North American Aerospace Defense Command, Joseph Cooper, Northeast Air Defense Sector, Jeremy Powell

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Technicians at NORAD’s Northeast Air Defense Sector (NEADS) try frantically to locate Flight 11 on their radar scopes, but are supposedly hindered by their outdated equipment. [Spencer, 2008, pp. 31-32] NEADS has just been alerted to the hijacking of Flight 11 (see (8:37 a.m.) September 11, 2001). [9/11 Commission, 7/24/2004, pp. 20] Its technicians realize they need to find the location of the hijacked plane quickly, so that the weapons team will be able to pass this information on to any fighter jets that are launched after it.
Locating Flight 11 Is a 'Grueling Process' - Author Lynn Spencer will later explain: “To identify American 11, the surveillance and ID techs must go through a grueling process. Their radar scopes are filled with hundreds of radar returns not just from aircraft but from weather systems, ground interference, and what’s called anomalous propagation—false returns caused by conditions in the atmosphere, or by such obstructions as flocks of birds. The technicians must first determine which radar data on their screens is for aircraft, which they do by monitoring its movement, which is distinctive for planes. The technician must observe for at least 36 seconds to a minute just to confirm that a blip is in fact an aircraft track. The tech must attach what’s called a tactical display number to it, which tells the computer to start tracking and identifying the target. If the target is in fact a plane, then over a period of 12-20 seconds, the computer will start to generate information on the track: heading, speed, altitude, latitude, longitude, and the identifying information being transmitted by the transponder.” However, Flight 11’s transponder has been switched off (see (Between 8:13 a.m. and 8:21 a.m.) September 11, 2001). Therefore, “With the hundreds of pieces of radar data filling their screens, and little information as to the location of the flight,” the task of locating it “is daunting.”
Radar Equipment Supposedly Unsuitable - Spencer will suggest that trying to locate Flight 11 is made more difficult because the radar equipment at NEADS is outdated and unsuited to the task at hand. She writes: “[T]he NEADS radar equipment is different from that used by air traffic controllers. It’s much older, developed in the 1970s and brought into use by NEADS in the early 1980s. The system was designed to monitor the shoreline for incoming high-altitude threats: missiles coming from across the ocean. Slow and cumbersome, and not nearly as user friendly as more modern equipment, the NEADS monochromic radar displays are not designed to take internal FAA radar data or to identify radar tracks originating from inside the United States. The system offers little, if any, such low-level coverage over the country.” [Spencer, 2008, pp. 31-32] Several of the NEADS personnel will later complain of their inability to locate Flight 11 on their scopes (see Shortly After 8:37 a.m. September 11, 2001). But Master Sergeant Joe McCain, the mission crew commander technician at NEADS, believes he has located Flight 11 on the radar screen just before it crashes into the World Trade Center (see 8:45 a.m.-8:46 a.m. September 11, 2001).

Entity Tags: Northeast Air Defense Sector

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

At the FAA’s Herndon Command Center, the national operations manager, Ben Sliney, learns more details of the hijacking of Flight 11, and becomes involved with the emergency response to it. [Spencer, 2008, pp. 21] A supervisor at the Command Center informed Sliney of the suspected hijacking at just before 8:30 (see 8:28 a.m. September 11, 2001). Soon after, the supervisor interrupted a meeting Sliney was in, to tell him American Airlines had called to report the deteriorating situation on Flight 11 (see 8:30 a.m.-8:40 a.m. September 11, 2001).
Sliney Receives More Details - Sliney heads to the center’s operations floor, where the supervisor gives him further details of the call from American Airlines, including information about flight attendant Betty Ong’s phone call from Flight 11 (see 8:19 a.m. September 11, 2001). The supervisor says the plane’s transponder has been switched off (see (Between 8:13 a.m. and 8:21 a.m.) September 11, 2001), which means no flight data is showing on the screens of air traffic controllers, and the latest information from the FAA’s Boston Center is that Flight 11 has turned south, and is now 35 miles north of New York City. On one of the large screens at the front of the Command Center that shows flight trajectories, Sliney can see that the track for Flight 11 is in “ghost.” This means that, because no transponder data is being received, the computer is displaying track information based on previously stored track data.
Sliney Seeks Information, Requests Teleconference - Sliney instructs his staff to contact facilities along the path the flight appears to be on, to find if anyone is in contact with it or tracking it. [Spencer, 2008, pp. 1 and 19-21] He will later recall, “I figured we’d try to get the people on the ground, the towers in the area, the police departments, anyone we could get to give us information on where this flight was.” [Canadian Broadcasting Corporation, 9/10/2006] Sliney then requests a teleconference between the FAA’s Boston Center, New York Center, and FAA headquarters in Washington, so they can share information about the flight in real time. [Spencer, 2008, pp. 21] The Command Center has already initiated a teleconference between the Boston, New York, and Cleveland Centers, immediately after it was notified of the suspected Flight 11 hijacking. [9/11 Commission, 8/26/2004, pp. 11] However, Sliney apparently does not request military assistance. According to author Lynn Spencer, “The higher echelons at headquarters in Washington will make the determination as to the necessity of military assistance in dealing with the hijacking.” [Spencer, 2008, pp. 21]

Entity Tags: Ben Sliney, Federal Aviation Administration

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Dave Bottiglia.Dave Bottiglia. [Source: ABC News]After Flight 11 appears on his radar screen, Dave Bottiglia, an air traffic controller at the FAA’s New York Center, is informed that this aircraft is suspected of having been hijacked. Flight 175 entered Bottiglia’s airspace not long before this (see 8:40 a.m. September 11, 2001). [MSNBC, 9/11/2002; 9/11 Commission, 8/26/2004, pp. 20] Its pilot has just told Bottiglia about the “suspicious transmission” (presumably from Flight 11) he heard while departing Boston airport (see 8:41 a.m.-8:42 a.m. September 11, 2001). [Gregor, 12/21/2001 pdf file] Seconds later, Flight 11 also enters the area Bottiglia is monitoring and its target appears on his radar screen. The controller sitting next to Bottiglia gets up and points to the radar blip. He says: “You see this target here? This is American 11. Boston Center thinks it’s a hijack.” Bottiglia will later recall that his initial thought about Flight 11, based on this information, is that the hijackers “were probably going to Cuba.” As its transponder has been turned off (see (Between 8:13 a.m. and 8:21 a.m.) September 11, 2001), he has no altitude information for Flight 11, but can tell from the radar scope that it appears to be descending. According to author Lynn Spencer: “Even without a transponder, controller radars calculate ground speed for all radar targets, and when a plane is descending, the ground speed decreases. The flight had been ‘grounding’ 600 knots, and now it has decreased to 320.” Bottiglia follows Flight 11’s target on his radar screen until it disappears over New York City. [MSNBC, 9/11/2002; Spencer, 2008, pp. 37] Because he is focused on Flight 11, Bottiglia will not notice when Flight 175’s transponder code changes at 8:47 (see 8:46 a.m.-8:47 a.m. September 11, 2001). [9/11 Commission, 7/24/2004, pp. 21; 9/11 Commission, 8/26/2004, pp. 21] The New York Center was first notified of Flight 11’s hijacking at 8:25 a.m. (see 8:25 a.m. September 11, 2001), though this information was not passed on to Bottiglia. [Federal Aviation Administration, 9/17/2001 pdf file; Spencer, 2008, pp. 36-37]

Entity Tags: Dave Bottiglia, New York Air Route Traffic Control Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline


Time period

Email Updates

Receive weekly email updates summarizing what contributors have added to the History Commons database


Developing and maintaining this site is very labor intensive. If you find it useful, please give us a hand and donate what you can.
Donate Now


If you would like to help us with this effort, please contact us. We need help with programming (Java, JDO, mysql, and xml), design, networking, and publicity. If you want to contribute information to this site, click the register link at the top of the page, and start contributing.
Contact Us

Creative Commons License Except where otherwise noted, the textual content of each timeline is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike