Communication problems and successes played an important role during the September 11 attacks in 2001 and their aftermath. Systems were variously destroyed or overwhelmed by loads greater than they were designed to carry, or failed to operate as intended or desired.

Attackers The organizers of the September 11, 2001 terrorist attacks apparently planned and coordinated their mission in face to face meetings and used little or no electronic communication. This "radio silence" made their plan more difficult to detect.

Federal government

According to 9/11 Commission staff statement No. 17 there were several communications failures at the federal government level during and after the 9/11 attacks. Perhaps the most serious occurred in an "Air Threat Conference Call" initiated by the National Military Command Center (NMCC) after two planes had crashed into the World Trade Center, but shortly before The Pentagon was hit. The participants were unable to include the Federal Aviation Administration (FAA) air traffic control command center, which had the most information about the hijackings, in the call.

According to the staff report: Operators worked feverishly to include the FAA in this teleconference, but they had equipment problems and difficulty finding secure phone numbers. NORAD asked three times before 10:03 to confirm the presence of FAA on the conference, to provide an update on hijackings. The FAA did not join the call until 10:17. The FAA representative who joined the call had no familiarity with or responsibility for a hijack situation, had no access to decision makers, and had none of the information available to senior FAA officials by that time.

We found no evidence that, at this critical time, during the morning of September 11, NORAD’s top commanders, in Florida or Cheyenne Mountain Complex, ever coordinated with their counterparts at FAA headquarters to improve situational awareness and organize a common response. Lower-level officials improvised—the FAA’s Boston Center bypassing the chain of command to contact NEADS. But the highest level Defense Department officials relied on the NMCC’s Air Threat Conference, in which FAA did not meaningfully participate.

First responders After the 1993 World Trade Center bombing, radio repeaters for New York City Fire Department communication were installed in the tower complex. Because they were unaware that several controls needed to be operated to fully activate the repeater system, fire chiefs at their command post in the lobby of the North Tower thought the repeater was not functioning and did not use it, though it did work and was used by some firefighters. When police officials concluded the twin towers were in danger of collapsing and ordered police to leave the complex, fire officials were not notified. Fire officials on the scene were not monitoring broadcast news reports and did not immediately understand what had happened when the first (South) tower collapsed.

There was little communication between New York City Police Department and fire department commands even though an Office of Emergency Management (OEM) had been created in 1996 in part to provide such coordination. A primary reason for OEM's inability to coordinate communications and information-sharing in the early hours of the WTC response was the loss of its emergency operations center, located on the twenty third floor of 7 World Trade Center, which had been evacuated after debris from the main tower's collapse struck the building. This ignited several fires that caused it to collapse at 5 pm later that day.

Emergency relief efforts in both Lower Manhattan and at the Pentagon were augmented by volunteer amateur radio operators in the weeks after the attacks.

Victims

Cell phones and in-plane credit card phones played a major role during and after the attack, starting with hijacked passengers who called family or notified the authorities about what was happening. Passengers and crew who made calls include: Sandra Bradshaw, Todd Beamer, Tom Burnett, Mark Bingham, Peter Hanson, Jeremy Glick, Barbara Olson, Renee May, Madeline Amy Sweeney, Betty Ong, Robert Fangman, Brian David Sweeney, and Ed Felt. Passengers and crew aboard United Airlines Flight 93 were able to assess their situation based on these conversations and plan a revolt that resulted in the aircraft crashing before reaching the hijackers’ intended target. According to the commission staff: "Their actions saved the lives of countless others, and may have saved either the U.S. Capitol or the White House from destruction."

According to the 9/11 Commission Report, 13 passengers from Flight 93 made a total of over 30 calls to both family and emergency personnel (twenty-two confirmed air phone calls, two confirmed cell phone and eight not specified in the report). Brenda Raney, Verizon Wireless spokesperson, said that Flight 93 was supported by several cell sites. There were reportedly three phone calls from Flight 11, five from Flight 175, and three calls from Flight 77. Two calls from these flights were recorded, placed by flight attendants: Betty Ong on Flight 11 and CeeCee Lyles on Flight 93.

Alexa Graf, an AT&T spokesperson, said it was almost a fluke that the calls reached their destinations. Marvin Sirbu, professor of Engineering and Public Policy at Carnegie Mellon University said on September 14, 2001, that "The fact of the matter is that cell phones can work in almost all phases of a commercial flight." Other industry experts said that it is possible to use cell phones with varying degrees of success during the ascent and descent of commercial airline flights.

After each of the hijacked aircraft struck the World Trade Center, people inside the towers made calls to family and loved ones; for the victims, this was their last communication. Other callers directed their pleas for help to 9-1-1. Over nine hours of the 9-1-1 calls were eventually released after petitioning by The New York Times and families of the WTC victims. In 2001, U.S. cell phones did not yet have the photography capabilities that became widespread by the mid-2000s.

General public After the attack, the cell phone networks of New York City and the Tri-State area were rapidly overloaded (a mass call event) as traffic doubled over normal levels. Cell phone traffic also overloaded across the East Coast, leading to crashes of the cell phone network. Verizon's downtown wire phone service was interrupted for days and weeks because of cut subscriber cables, and to the 140 West Street exchange being shut for days. Capacity between Brooklyn and Manhattan was also diminished by cut trunk cables.

Following the attacks, the issues with the cell network weren't resolved until 36 cellular COWs (cell towers on wheels) were deployed by September 14, 2001, in Lower Manhattan to support the U.S. Federal Emergency Management Agency (FEMA) and provide critical phone service to rescue and recovery workers.

Since three of the major television broadcast network owned-and-operated stations had their transmission towers atop the North Tower (One World Trade Center), coverage was limited after the collapse of the tower. The FM transmitter of National Public Radio station WNYC was also destroyed in the collapse of the North Tower and its offices evacuated. For an interim period, it continued broadcasting on its AM frequency and used NPR's New York offices to produce its programming.

The satellite feed of one television station, WPIX, froze on the last image received from the WTC mast; the image (a remote-camera shot of the burning towers), viewable across North America (as WPIX is available on cable TV in many areas), remained on the screen for much of the day until WPIX was able to set up alternate transmission facilities. It shows the WTC at the moment power cut off to the WPIX transmitter, prior to the towers' collapse.

During the September 11 attacks, WCBS-TV channel 2 and WXTV-TV channel 41 stayed on the air. Unlike most other major New York television stations, WCBS-TV maintained a full-powered backup transmitter at the Empire State Building after moving its main transmitter to the North Tower of the World Trade Center. The station was also simulcasted nationally on Viacom (which at the time owned CBS) cable network VH1 that day. In the immediate aftermath of the attacks, the station lent transmission time to the other stations who had lost their transmitters, until they found suitable backup equipment and locations.

The Emergency Alert System was never activated in the terrorist attacks, as the extensive media coverage made it unnecessary.

AT&T eliminated any costs for domestic calls originating from the New York City area (phones using area codes 212, 718, 917, 646, and 347) in the days following 9/11.

Radio communications

Radio communications during the September 11 attacks served a vital role in coordinating rescue efforts by New York Police Department, New York Fire Department, Port Authority Police Department, and emergency medical services.

While radio communications were modified to address problems discovered after the 1993 World Trade Center bombing, investigations into the radio communications during the September 11 attacks discovered that communication systems and protocols that distinguished each department was hampered by the lack of interoperability, damaged or failed network infrastructure during the attack, and overwhelmed by simultaneous communication between superiors and subordinates.

Background

A rough time line of the incident could include: 08:46 hrs.: American 11 crashes into the North Tower, a.k.a. 1 World Trade Center, (0 minutes elapsed time). 09:03 hrs.: United 175 crashes into the South Tower, a.k.a. 2 World Trade Center, (17 minutes elapsed time). 09:58 hrs.: South Tower, a.k.a. 2 World Trade Center collapses, (55 minutes after aircraft impact, 72 minutes elapsed time). 10:28 hrs.: North Tower, a.k.a. 1 World Trade Center collapses, (102 minutes elapsed time and post-impact).

The scale of the incident was described in the National Commission report on the attacks as unprecedented. In roughly seventeen minutes from 8:46 to 9:03 am, over a thousand police, fire, and emergency medical services (EMS) staff arrived at the scene.National Commission on Terrorist Attacks on the United States, (New York: W.W. Norton and Co., 2002) pp. 293. The report is a federal government report created by federal employees in the performance of their jobs. There are no copyright legends or statements inside the publication. Therefore, the entire book is believed to be in the public domain. At some point during a large incident, any agency will reach a point where they find their resources overrun by needs. For example, the Port Authority Police could not schedule staff as if a September 11 attack would occur every shift. There is always a balance struck between readiness and costs. There is conflicting data but some sources suggest there may have been 2,000 to 3,000 workers involved in the rescue operation. It would be rare for most agencies to see an event where there were that many people to be rescued.