Communication during the September 11 attacks
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.
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.
21 After the 1993 World Trade Center bombing, radio repeaters for New York City Fire Department communication were installed in the tower complex.
[citation needed] Emergency relief efforts in both Lower Manhattan and at the Pentagon were augmented by volunteer amateur radio operators in the weeks after the attacks.
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.
[7] 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.
[9] 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.
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.
The 9/11 Commission report suggests people in the NYPD 9-1-1 center and New York City Fire Department (FDNY) dispatch would benefit from better situation awareness.
[15] NIST concluded, at the beginning of the incident, there was an approximate factor of five (peak) increase in radio communications traffic over a normal level.
26 Red Book audio CDs of New York City Fire Department radio transmissions, covering the incident's initial dispatch and the tower failures, were reviewed.
Some transmissions had choppy audio possibly representative of interference from FSK paging or intermittent microwave radio paths to one or more receiver sites.
The documentary film gives different information, with a Fire Department member from Engine 7/Ladder 1 claiming that the aircraft's impact caused the system to fail.
A remote control console was connected to the repeater allowing staff at the North Tower lobby command post to communicate without using a hand-held radio.
In a review of the logging recorder track of the Port Authority repeater, someone arrived early during the incident and began to establish a command post.
From the command post in the lobby of the North Tower (1 World Trade Center), the user can be heard trying to transmit using a remote control unit.
The fact that users pressing buttons on the remote control can clearly be heard on the logging recorder shows the transmit audio path was working.
[25][26] The Commission report says the North Tower lobby command may not have worked because of a technical problem, the volume control turned all the way down, or because a button that must be pressed to enable it had not been pushed.
It's possible that by the random button pressing, a user sent a function tone that temporarily put the base station in monitor and that's what caused the outside agency's traffic to be heard.
[28] An oral history interview revealed the Port Authority UHF radios were normally used at incidents inside the World Trade Center.
The dense RF interference environment created in NYC that day was essentially a 'perfect storm'; one in which a radio designed 25 years prior could not possibly contend with.
[39] The federal 9/11 Commission Report included recommendations on communications systems used by police, fire, and emergency medical services (EMS) at the WTC incident.
Commission member Lee Hamilton, in several television appearances related to a 2006 book on the topic of the WTC incident, reiterated this factually correct view.
Similarly, if the Manhattan EMS dispatcher can't reach an ambulance because they are on one of the fire channels, patient care is affected.
New York City Police Commissioner Raymond Kelly, appearing on the Charlie Rose show, expressed his view that the existing radio systems performed satisfactorily during the WTC incident.
[43] In Hurricane Katrina's wake, a sergeant in the Louisiana Department of Wildlife and Fisheries appeared on national television to describe not being able to reach persons from other agencies who were assisting with the recovery.
One approach to cross-department netting is the capability of some modern trunked systems to provide a function called dynamic regrouping; a feature that Motorola doesn't support in simplex (e.g. 'fireground') operations.
The feature allows the dispatch center personnel to send units from different agencies who are responding to the same incident to a common talk group or virtual channel.
[46] It is also true that most trunked radio system users are likely to hear busy signals, (error tones showing no channels are available,) for the first time during a large disaster.
