A special radio transmitter that is carried by aircraft and designed to go off automatically if a plane crashes is activated in the New York area, more than two minutes before Flight 11 hits the World Trade Center. [New York Times, 10/16/2001; 9/11 Commission, 10/1/2003 
; Aircraft Owners and Pilots Association, 1/22/2009]
Pilots Inform Controller of Emergency Signal – At 8:44 a.m. and 5 seconds, David Bottiglia, an air traffic controller at the FAA’s New York Center, receives information from one of the aircraft he is monitoring. The pilot of US Airways Flight 583 tells him: “I just picked up an ELT [emergency locator transmitter] on 121.5. It was brief, but it went off.” [New York Times, 10/16/2001; 9/11 Commission, 10/1/2003 ] (121.5 megahertz is an emergency frequency that ELTs transmit their distress signals on. [Aircraft Electronics Association, 2009, pp. 36 ; Aircraft Owners and Pilots Association, 1/22/2009] ) A minute later, at 8:45 a.m. and 8 seconds, Bottiglia hears the same thing from another of the aircraft he is monitoring. The pilot of Delta Airlines Flight 2433 tells him, “We picked up that ELT too, but it’s very faint.” [New York Times, 10/16/2001] However, Flight 11 has not yet crashed, and will hit the WTC over 90 seconds later, at 8:46 a.m. and 40 seconds (see 8:46 a.m. September 11, 2001). [9/11 Commission, 7/24/2004, pp. 7]
ELTs Help Locate Crashed Aircraft – An emergency locator transmitter, or ELT, is a small electronic device, which is designed to automatically begin emitting a continuous and distinctive radio signal when subjected to crash-generated forces, so as to facilitate the locating of an aircraft if it crashes. ELTs are carried aboard most general aviation aircraft in the US and are usually located far back in the plane’s fuselage or in the tail surface, so that they will suffer only minimal damage in the event of a crash impact. [Federal Aviation Administration, 3/23/1990; US Department of the Army, 8/12/2008, pp. E-6 ; Aircraft Electronics Association, 2009, pp. 36 ; Aircraft Owners and Pilots Association, 1/22/2009]
Location Signal Comes from Unclear – The precise location from where the ELT signal is being transmitted is unclear. Around the time Flight 11 crashes, a participant in an FAA teleconference will say the signal was coming from the area Flight 11’s track was in before it disappeared from primary radar, about 20 miles from New York’s JFK International Airport. [Federal Aviation Administration, 9/11/2001] Peter McCloskey, a traffic management coordinator at the New York Center, will tell the 9/11 Commission that the ELT goes off “in the vicinity of Lower Manhattan.” [9/11 Commission, 10/1/2003 ]
Many Signals Are False Alarms – ELT signals not determined to be false alarms are reported to the Air Force Rescue Coordination Center (AFRCC) at Langley Air Force Base in Virginia. [9/11 Commission, 10/1/2003 ] Major Allan Knox, who works at the AFRCC, will tell the 9/11 Commission that he does not recall being informed of any ELT signals on September 11, but says the AFRCC will review its data to verify this statement. He will also say that at least 20 ELT signals go off each day, and that 97 percent of ELT signals are false alarms. [9/11 Commission, 10/6/2003 ]
ELT Signal Is ‘Clearly Indicative of a Crash’ – However, Paul Thumser, an operations supervisor at the FAA’s New York Center with 20 years’ experience as an air traffic controller, and who is also an experienced airline pilot, will tell the 9/11 Commission that the ELT in a Boeing 767 cannot be triggered by the pilot. (The two aircraft that hit the WTC are 767s.) He will also say that the sensitivity setting for the ELT in a 767 is not low, and so it should be impossible for a hard turn or a hard landing to accidentally cause the ELT to go off. Thumser will say that “he judged it would have to be a serious impact to set the ELT off.” [9/11 Commission, 10/1/2003 ] Terry Biggio, the operations manager at the FAA’s Boston Center, will similarly tell the 9/11 Commission that an ELT signal “is clearly indicative of a crash.” [9/11 Commission, 9/22/2003]
FAA Manager Believes Signal Unrelated to Flight 11 Crash – Noting that the ELT goes off prior to Flight 11 hitting the WTC, Mike McCormick, the manager of the FAA’s New York Center, will tell the 9/11 Commission that his “best hypothesis” is that the activation of an ELT at this time is “unrelated to the event” of Flight 11 crashing. [9/11 Commission, 12/15/2003 ] However, there are no reports of an ELT going off at the time when Flight 11 hits the WTC. Furthermore, another ELT will be activated in the New York area around five minutes before the second plane hits the WTC (see 8:58 a.m. September 11, 2001). [Federal Aviation Administration, 9/11/2001, pp. 37 ] Despite the pilots’ reports of picking up an ELT signal just before Flight 11 crashes, the AFRCC will inform the 9/11 Commission that a “historical ELT data search” found “no ELT signal being heard by the satellites” for the area within a radius of 50 nautical miles (about 57.5 miles) of JFK International Airport between 8:00 a.m. and 10:30 a.m. on this day. [9/11 Commission, 2003]
9:03 a.m. September 11, 2001: Boston Center Tells FAA Regional Office that Hijackers Said ‘We Have Planes’; Office Suggests Notifying Military
Over an FAA teleconference, Terry Biggio, the operations manager at the FAA’s Boston Center, reports to the FAA’s New England regional office the “We have some planes” comment apparently made by a Flight 11 hijacker at 8:24 a.m. (see 8:24 a.m. September 11, 2001). [9/11 Commission, 8/26/2004, pp. 23; Spencer, 2008, pp. 79-80] Because the Boston Center controller monitoring Flight 11 had not understood the communication, the center’s quality assurance specialist had been instructed to “pull the tape” of the transmission, listen to it carefully, and then report back. [9/11 Commission, 7/24/2004, pp. 19] Biggio now reports to the New England region representative: “I’m gonna reconfirm with, with downstairs, but the, as far as the tape, Bobby seemed to think the guy said that ‘we have planes.’ Now, I don’t know if it was because it was the accent, or if there’s more than one [hijacked plane], but I’m gonna, I’m gonna reconfirm that for you, and I’ll get back to you real quick. Okay?” Another participant in the teleconference asks, “They have what?” and Biggio clarifies: “Planes, as in plural.… It sounds like, we’re talking to New York, that there’s another one aimed at the World Trade Center.… A second one just hit the Trade Center.” The New England region representative replies: “Okay. Yeah, we gotta get—we gotta alert the military real quick on this.” [9/11 Commission, 6/17/2004 ; 9/11 Commission, 7/24/2004, pp. 23] A manager at the FAA’s Command Center in Herndon, Virginia, is monitoring the teleconference, and so also learns of the “We have some planes” communication at this time (see 9:03 a.m. September 11, 2001). [Spencer, 2008, pp. 79-80] At 9:05 a.m., Biggio will confirm for the New England region representative—with the Command Center listening in—that a hijacker said, “we have planes” (forgetting the “some”). [9/11 Commission, 6/17/2004 ; 9/11 Commission, 8/26/2004, pp. 24]
9:03 a.m. September 11, 2001: FAA Command Center Learns of Hijackers’ ‘We Have Some Planes’ Communication
At the FAA’s Command Center in Herndon, Virginia, manager John White learns of the communication apparently made by a hijacker on Flight 11, stating “We have some planes” (see 8:24 a.m. September 11, 2001), and quickly notifies the national operations manager of this. Terry Biggio, the operations manager at the FAA’s Boston Center, is relaying all the information he has about Flight 11 to the Command Center’s teleconference. In the conference room at the Command Center, White is listening in. [Spencer, 2008, pp. 79-80] Because the air traffic controller monitoring Flight 11 had not understood the “We have some planes” hijacker communication, the Boston Center’s quality assurance specialist had been instructed to “pull the tape” of the transmission, listen to it carefully, and then report back. [9/11 Commission, 7/24/2004, pp. 19] Having learned that the specialist has deciphered the transmission, Biggio now relays the details of it over the teleconference. Seconds later, those at the Command Center see Flight 175 crashing into the South Tower of the World Trade live on CNN. White promptly dispatches a manager to pass on the details of the transmission to Ben Sliney, the national operations manager at the Command Center (see 9:06 a.m. and After September 11, 2001). [Spencer, 2008, pp. 79-80] The FAA’s New England regional office also learns of the “We have some planes” communication at this time (see 9:03 a.m. September 11, 2001). [9/11 Commission, 8/26/2004, pp. 23]
9:07 a.m. September 11, 2001: Boston Center Manager Wants Cockpit Security Warnings Sent to Aircraft
After conferring with the FAA’s New England regional office and contacting representatives of the Air Transport Association, the FAA’s Boston Center decides to issue a Notice to Airmen, warning pilots to heighten cockpit security. [9/11 Commission, 8/26/2004, pp. 24-25] Following the second attack on the World Trade Center, Terry Biggio, the operations manager at the Boston Center, is concerned that there may be additional attacks. He therefore asks a manager at the FAA’s New England regional office if warnings could be sent to airborne aircraft via “ACARS or something,” advising them to increase their cockpit security. [9/11 Commission, 8/26/2004, pp. 24] (ACARS is an e-mail system that allows personnel on the ground to rapidly communicate with those in the cockpit of an aircraft. [9/11 Commission, 8/26/2004, pp. 9] ) Biggio is particularly concerned about the need to warn airborne international flights that are scheduled to arrive at New York’s JFK International Airport. On the advice of a New England Region representative, Boston Center decides to contact Air Transport Association representatives through the FAA’s Herndon Command Center and ask them to formally request that airlines warn their aircraft to heighten cockpit security. According to the 9/11 Commission, though, Biggio is “[n]ot content to rely on the airlines to warn their aircraft,” and so decides that the Boston Center will issue a Notice to Airmen (“NOTAM”) to heighten cockpit security in light of the attacks in New York. [9/11 Commission, 8/26/2004, pp. 24-25] The NOTAM system is the communication method used to define the rules of the day for air traffic controllers and pilots. With the status of equipment, airports, and rules changing frequently, the NOTAM system is used to distribute any changes to all pilots and controllers. [Freni, 2003, pp. 86] Two or three minutes later, controllers at the Boston Center will contact all the aircraft in their airspace by radio and advise them to increase cockpit security (see 9:09 a.m.-9:10 a.m. September 11, 2001). [9/11 Commission, 8/26/2004, pp. 25]
9:09 a.m.-9:10 a.m. September 11, 2001: Boston Center Controllers Give Cockpit Security Alert to All Their Aircraft
Terry Biggio, the operations manager at the FAA’s Boston Center, instructs the air traffic controllers at his center to contact all aircraft in the center’s airspace by radio and inform them of the events taking place in New York. He tells the controllers to also advise the aircraft to heighten their cockpit security in light of these events. [9/11 Commission, 7/24/2004, pp. 23; 9/11 Commission, 8/26/2004, pp. 25] According to author Lynn Spencer, previously “No transmission of that kind has ever been made on air traffic control frequencies.” Controller Jim Ekins is the first to act. He announces over all the radio frequencies in the sector: “All aircraft! Due to recent events that have unfolded in the Boston sector, you are advised to increase cockpit security. Allow no entry to your cockpit!” According to Spencer, other controllers nearby overhear and realize: “Yes! That’s exactly what we need to tell them!” [Spencer, 2008, pp. 98] The Boston Center air traffic controllers then immediately execute Biggio’s order, and give the warning to their aircraft. [9/11 Commission, 8/26/2004, pp. 25] However, Spencer will write: “Communications with controllers are [usually] as dry as they come, and to many pilots this announcement is so out of their realm of understanding, training, and experience that it simply doesn’t make sense. It actually agitates some, who cannot help but view it as some new kind of ‘FAA bureaucratic bullsh_t.’” [Spencer, 2008, pp. 99] Boston Center will subsequently ask the FAA’s Herndon Command Center to issue a similar cockpit security alert nationwide, but the Command Center apparently will not act on this request (see (9:15 a.m.) September 11, 2001). [9/11 Commission, 7/24/2004, pp. 23] United Airlines will issue a company-wide order at 9:21 for its dispatchers to warn their flights to secure their cockpits (see 9:21 a.m. September 11, 2001). [9/11 Commission, 1/27/2004; 9/11 Commission, 7/24/2004, pp. 455]
