Washington U.S. investigators now believe that a hijacker in the cockpit aboard United Airlines Flight 93 instructed terrorist-pilot Ziad Jarrah to crash the jetliner into a Pennsylvania field because of a passenger uprising in the cabin.
This theory, based on the government's analysis of cockpit recordings, discounts the popular perception of insurgent passengers grappling with terrorists to seize the plane's controls.
The government's findings -- laid out deep within the report on the Sept. 11, 2001, attacks that last month was sent to Congress -- aim to resolve one of the enduring mysteries of the deadliest terror attacks in U.S. history: What happened in the final minutes aboard Flight 93?
The FBI strenuously maintains that its analysis does not diminish the heroism of passengers who -- with the words "Let's roll" -- apparently rushed down the airliner's narrow aisle to try to overtake the hijackers.
President Bush and Atty. Gen. John Ashcroft have regularly praised the courage of those aboard Flight 93, some of whom told family members by telephone they were planning to storm the cockpit.
"While no one will ever know exactly what transpired in the final minutes of Flight 93, every shred of evidence indicates this plane crashed because of the heroic actions of the passengers," FBI spokeswoman Susan Whitson said Thursday.
Thirty-three passengers, seven crew members and the four hijackers died.
Citing transcripts of the still-secret cockpit recordings, FBI Director Robert Mueller told congressional investigators in a closed briefing last year that, minutes before Flight 93 hit the ground, one of the hijackers "advised Jarrah to crash the plane and end the passengers' attempt to retake the airplane."
Jarrah is thought to have been the terrorist-pilot because he was the only of the four hijackers aboard known to have a pilot's license. The congressional report describes the hijackers wearing bandanas and carrying knives, and several passengers reported seeing the captain and co-pilot lying on the floor of the first-class section, presumably dead.
Mueller's description was disclosed in a brief passage far into the 858-page report to Congress. Previous statements by FBI and other government officials have been ambiguous about what occurred in the cockpit.
The same cockpit recording was played privately in April 2002 for family members of victims aboard Flight 93, and the FBI also provided them with its best effort at producing an understandable transcript.
Some family members indicated afterward they were led to believe that passengers used a food cart as a shield and successfully broke into the cockpit.
"It is totally obvious listening to that flight recorder that they made it into the cockpit," said Deena Burnett, who lost her husband, Thomas E. Burnett Jr., on Flight 93.
"You cannot listen to the tape and understand it any other way," Burnett said Thursday in a telephone interview.
She declined to discuss specific things she heard on the tape because U.S. prosecutors have asked families not to describe the recording. She said she does remember hearing a hijacker telling Jarrah in Arabic to crash the plane deliberately, as Mueller described, and Jarrah refusing to crash it.
Burnett also said U.S. authorities, including Assistant U.S. Attorney David Novak, told families explicitly in April 2002 that the recording indicates passengers actually made their way into the cockpit.
The FBI has been loath to publicly put forward a contradictory theory out of sensitivity to the families and because of uncertainty about what happened.
People who have heard the recording describe it as nearly indecipherable, containing static noises, cockpit alarms and wind interspersed with cries in English and Arabic. Near the end of the tape, sounds can be heard of breaking glass and crashing dishes -- lending credence to the theory that passengers used the food cart to rush the jetliner's narrow aisle.
Separately, the data recorder showed the plane's wings rocking violently as the jet flew too low and too fast for safe flight.
Intelligence officials believe the likely target for Flight 93 was the White House, based on information from Abu Zubaydah, a senior al-Qaida terrorist leader in U.S. custody who is believed to have played a key role in organizing the Sept. 11 attacks.
Prosecutors have sought a U.S. judge's permission to play recordings from Flight 93 during the terrorism trial of Zacarias Moussaoui, the only defendant in a U.S. case prosecutors have directly tied to the attacks. Moussaoui is accused of conspiring with the hijackers.
The government has said it can link Moussaoui to Jarrah, using a telephone number found on a business card recovered at the Shanksville, Pa., crash site. Prosecutors believe the card belonged to Jarrah and that Moussaoui had called the same number.
Moussaoui has acknowledged allegiance to Osama bin Laden and al-Qaida but says he was not involved in the attacks.