Image courtesy of Department of Justice, Federal Bureau of Investigation This is a summary page for the Flight 93 Cockpit Voice Recorder (CVR) which includes a downloadable copy of the original Cockpit Voice Recorder Transcript. The audio of the Flight 93 Cockpit Voice Recorder is sealed from being publicly released by the Federal Bureau of Investigation (FBI) as this is still an active and ongoing investigation. For more information about Black Boxes and the story of Flight 93 visit the Glossary page. The Cockpit Voice Recorder, also known as the CVR, records radio transmissions and sounds in or near the cockpit. The Cockpit Voice Recorder records the flight crew voices, as well as other sounds inside the cockpit using microphones usually located in the overhead instrument panel between the pilot and co-pilot as well as in their headsets. Sounds of interest to an investigator include engine noise, still warnings, landing gear extension and retraction, and other recognizable clicks and pops. Communications with Air Traffic Control and conversations between pilots and cabin crew are also recorded by the Cockpit Voice Recorder.
The Cockpit Voice Recorder is made of stainless steel or titanium and is made to withstand high impact velocity or crash impact of 3,400 g-force and temperatures up to 2000 degrees Fahrenheit (1,100 degrees Celsius) for at least 30 minutes. The recorder inside is wrapped in a thin layer of aluminum and a layer of high temperature insulation. The Cockpit Voice Recorder of Flight 93 was recovered on Friday, September 14 at 8:30 pm, from the crater at a depth of 25 feet. The FBI assumed custody of the box and flew it to the National Transportation Safety Board (NTSB) headquarters in Washington D.C. and then to the Honeywell facilities in Redmond, Washington for evaluation and downloading.
In the weeks following, the Flight 93 Cockpit Voice Recorder yielded evidence of increased importance. At the World Trade Center site, none of the four black boxes on the two hijacked aircraft were recovered in the building rubble. At the Pentagon site, both boxes from Flight 77 were recovered, but the Cockpit Voice Recorder was so badly damaged that it did not yield usable information. Normally, the audio of a Cockpit Voice Recorder recovered from a crash scene is heard only by the team of investigators and representatives of the airline and the aircraft manufacturer and others who can assist in accurately interpreting the recording. In the case of Flight 93, family members of the passengers and crew began lobbying for permission to hear the recording within months of their loved ones’ death. Eventually, permission was granted, and in April 2002, the FBI invited representatives of each family to a secure, private location to listen to the audio while viewing the transcript. They were asked not to speak with the media or others about what they heard pending use of the recording in criminal proceedings against terrorists associated with the hijacking. The transcript of the Cockpit Voice Recording from Flight 93 was publicly released in April 2006 during the sentencing trial of Zacarias Moussaoui. The audio of the Flight 93 Cockpit Voice Recorder is sealed by the Federal Bureau of Investigation (FBI) as this remains an active and ongoing investigation.
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Last updated: October 31, 2023