Radio communications during the September 11 attacks

Communication problems and successes played an important role in the September 11, 2001 attacks 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.

The organizers of the September 11, 2001 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.

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.

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