Newly released audio shows the shock, confusion of September 11, 2001

As 10-year commemorations of 9/11 get under way, the public now has access to a number of previously unreleased audio recordings from the morning of September 11, 2001.

A newly released cache of 114 audio recordings paints an intimate and unsettling portrait of the confusion that engulfed civilian air-traffic controllers, military aviation officers, and airline and fighter-jet pilots during two crucial hours on the morning of September 11, 2001.

The recordings, many of which had not previously been available to the public, show how intercommunication broke down, with civilians and military officials at odds over where the missing airliners had gone and what should be done in response.

At one point, a military official learns that he has dispatched fighter jets to intercept an airliner that has already crashed. In New York, a controller realizes that the missing airliner he is trying to find is visible outside his window, turning toward the second tower of the World Trade Center.

The tapes also suggest that military jets were never trailing the four hijacked airliners, ready to shoot them down, as Bush administration officials had suggested at the time, according to an analysis by The New York Times, which first reported on the release of the recordings.

The audio further reveals the shock and horror of those who witnessed the morning's events. At one point, one of the hijackers, Mohamed Atta, is heard over a radio instructing passengers on American Airlines Flight 11. Later, screams and gasps reverberate in an air-traffic control room as United Airlines Flight 175, seemingly out of nowhere, crashes into the South Tower of the World Trade Center.

The multimedia document was culled from the archives of 9/11 commission by Miles Kara, a retired Army colonel and investigator for the 9/11 commission, aided by students from the Rutgers School of Law.

Investigators of the 9/11 commission, which was set up just over a year after 9/11, started compiling the recordings and transcripts but had not completed it in time to be released with the report, which was released on July 22, 2004.

This is not the first time any of the audio has aired publicly. Some of the recordings had been played during the 9/11 commission hearings in 2004. The rest were transferred to the National Archives after the commission was shut down that same year.

According to The New York Times, one key tape from the last half-hour in the cockpit of United Flight 93, which crashed in Pennsylvania, remains unreleased. That tape was played at the trial for one of the plotters, but the families of the passengers who attempted to regain control of the plane requested the audio not be made public.