Previously unreleased transcripts of cockpit discussions between two of the terrorists who hijacked United Airlines Flight 93 on Sept. 11, 2001, leave little doubt that a passenger uprising forced them to crash the plane into a field in Somerset County.

The rebellion likely averted a strike on a major public building in Washington, according to yesterday's report by the independent commission investigating the Sept. 11 attacks.

The 567-page report also casts new light on the four Flight 93 hijackers, including details that show Ziad Jarrah, the group's leader, apparently was one of the key operatives in the overall plot.

Forty-four people, including the hijackers, died when Flight 93 crashed into a field outside the Somerset County town of Shanksville.

The commission put the time of the Flight 93 hijacking at 9:28 a.m. while the plane was at 35,000 feet above eastern Ohio. The plane suddenly dropped to 700 feet altitude.

"Eleven seconds into the descent, the FAA's air traffic control center in Cleveland received the first of two radio transmissions from the aircraft. During the first broadcast, the captain or first officer could be heard declaring 'mayday' amid the sounds of a physical struggle in the cockpit. The second radio transmission, 35 seconds later, indicated that the fight was continuing. The report says the captain or first officer could be heard shouting: 'Hey get out of here, get out of here, get out of here.' "

The report includes a transcript of conversation captured by the cockpit voice recorder that shows the uprising started at 9:57 a.m., almost half an hour after the hijacking began, when passengers on board learned through cell phone conversations with family members that three other hijacked planes had been flown into buildings in New York and Washington.

As passengers began beating on the cockpit door, the report says, Jarrah rolled the airplane left and right, attempting to knock the passengers off balance. At 9:58:57, the report says, Jarrah began to nose the airplane up and down to topple the passengers outside the cabin door.

"The recorder captured the sounds of loud thumps, crashes, shouts and breaking glasses and plates," the report states. At five seconds after 10 a.m., the recorder captured a conversation between Jarrah and another person, apparently another hijacker in the cockpit.

"Is that it? Shall we finish it off?" Jarrah asks the other person.

The other hijacker responds, "No. Not yet. When they all come, we finish it off."

Fighting continues to be heard outside the cockpit. At that point a passenger is heard shouting, "In the cockpit. If we don't we'll die!"

Sixteen seconds later, a passenger yells, "Roll it!"

While the report does not state so, previous reports indicated that passengers might have used a beverage cart in an attempt to knock down the cockpit door.

At 10:01, the federal Command Center received a report from an aircraft that had seen United 93 "waving his wings" 20 miles northwest of Johnstown.

"The aircraft had witnessed the hijackers' efforts to defeat the passengers' counterattack," the report says.

At 10:01 a.m. Jarrah stopped the violent maneuvers with the airplane and said, "Allah is the greatest! Allah is the greatest!" He is then heard asking the other hijacker, "Is that it? I mean, shall we put it down?"

The other replies, "Yes, put it in, and pull it down."

According to the report, the passengers did never reached the cockpit, but the hijackers "must have judged that the passengers were only seconds from overcoming them. The airplane rolled onto its back, and one of the hijackers began shouting, "Allah is the greatest. Allah is the greatest."

The aircraft struck the earth at 580 mph outside Shanksville, 20 minutes' flying time from Washington. A passing National Guard cargo plane, which had earlier seen American Airlines Flight 77 strike the Pentagon, was passing over the Johnstown area at that point. It reported seeing black smoke rising from the ground near Johnstown.

"Jarrah's objective," the report says, "was to crash his airliner into symbols of the American republic, the Capitol or the White House. He was defeated by the alerted, unarmed passengers of United 93."

Along with chief hijacker Mohamed Atta, Jarrah, a Lebanese citizen, traveled to Kandahar, Afghanistan, in 1999 to meet with al-Qaida leaders. Earlier plans to fight on behalf of Chechen rebels against the Russian Army fell through when they had difficulty entering the breakaway former Soviet republic.

While Jarrah apparently became involved in the 9/11 plot while studying dentistry in Germany, where he was drawn into a cell of Islamic extremists, the three other Flight 93 hijackers, Saeed al-Ghamdi, Ahmed al Nami and Ahmad al Haznawi, were recruited in Afghanistan after they failed to get into Muslim Chechnya to fight against Russia in 1999.

"While training at al-Qaida camps, a dozen of them heard [Osama] bin Laden's speeches, volunteered to become suicide operatives and eventually were selected as muscle hijackers for the planes operation," the report says.

Ghamdi and Nami apparently received training in firearms, heavy weapons, explosives and topography at the al Faruq camp near Kandahar.

An al-Qaida official arranged for Nami and a companion, Mushabib al Hamlan, to meet Bin Laden "and instructed them to use the following phrase to express their desire to become martyrs:

" 'I want to be one of this religion's bricks and glorify this religion.' "

Bin Laden, the report states, accepted both applicants. Ultimately, only Nami joined the Sept. 11 attacks, ending his journey from Afghanistan to America in a field in Somerset County.