Search crews have found the cockpit voice recorder from United Flight 93 that could reveal whether passengers tried to gain control of the hijacked plane before it crashed in a Pennsylvania field.
The "black box" was discovered buried 25 feet deep in the crash site crater, FBI spokeswoman Linda Vizi said. It was sent to the National Transportation Safety Board in Washington. FBI spokesman Bill Crowley said the recorder appears to be "in fairly good shape," citing descriptions by those who found it.
The recorder is designed to capture at least the last 30 minutes of cockpit conversation. The plane's other black box, the flight data recorder, was found on Thursday.
The Boeing 757 left Newark, New Jersey, on Tuesday morning, bound for San Francisco with 45 people on board. Radar showed the plane was over Cleveland when it abruptly turned back east, began losing altitude and flying erratically before it crashed in western Pennsylvania.
Cell phone calls made by passengers to relatives before the crash suggested they planned to wrest control of the jet from the hijackers and prevent it becoming a missile like the ones that toppled the World Trade Centre and hit the Pentagon.
Some have speculated that the hijackers planned to target Camp David in Maryland, the Capitol or the White House.
In a tribute Friday night that brought friends and relatives of the dead to tears, Governor Tom Ridge called some of the passengers heroes for battling with their captors.
"The passengers on that plane decided to fight back their hijackers," Ridge said at a vigil attended by thousands. "They undoubtedly saved hundreds, if not thousands, of lives in the process. They sacrificed themselves for others ? the ultimate sacrifice."
"What appears to be a charred, smoldering hole in the ground is truly and really a monument to heroism," he said.Reuse content