8:00 a.m.: American Airlines Flight 11, carrying 81 passengers and 11 crew members, begins its takeoff from Logan Airport in Boston, Massachusetts en route to Los Angeles.

8:13 a.m.: An air controller instructs American 11 to climb to 35,000 feet, and the aircraft fails to respond. The controller tries using the emergency frequency to contact the aircraft but there is no response.

8:14 a.m.: United Airlines Flight 175, carrying 56 passengers and nine crew members on board, takes off from Logan Airport in Boston, Massachusetts.

8:20 a.m.: American Flight 77 takes off from Dulles International Airport.

8:21 a.m.: American Flight 11 turns off its transponder.

8:24 a.m.: This transmission comes from American 11: "We have some planes. Just stay quiet, and you'll be okay. We are returning to the airport" ("We have some planes," was unintelligible.) Seconds later another statement follows: "Nobody move. Everything will be okay. If you try to make any moves, you'll endanger yourself and the airplane. Just stay quiet."

8:28 a.m.: The FAA's Boston Center calls FAA Command Center in Herndon, Virginia, and reports that American 11 has been hijacked.

8:34 a.m.: Boston Center receives another transmission from American 11: "Nobody move please. We are going back to the airport. Don't try to make any stupid moves."

8:37 a.m.: Boston Center informs NORAD of American 11's hijacking. It is the first notice the military receives of the unfolding events.

FAA: "Hi. Boston Center TMU, we have a problem here. We have a hijacked aircraft headed towards New York, and we need you guys, we need someone to scramble some F-16s or something up there, help us out."

NORAD: "Is this real-world or exercise?"

FAA: "No, this is not an exercise, not a test."

8:41 a.m.: United 175 enters New York airspace.

8:42 a.m.: United Flight 93 takes off from the airport in Newark, New Jersey.

8:46 a.m.: In response to American 11's hijacking, Otis Air Force Base receives an order to scramble F-15s. Military officials ask for a destination for the fighter planes. None is known. At the same time of the order, American 11 crashes into the World Trade Center North Tower.

8:47 a.m.: United 175 changes its transponder code twice. The changes go unnoticed because the same controller assigned to it is looking for American 11.

8:48 a.m.: The FAA's New York Center, unaware of American 11 crashing, talks to the FAA Command Center in a teleconference concerning that flight. "This is New York Center. We're watching the airplane...They've told us that they believe one of their stewardesses was stabbed and that there are people in the cockpit that have control of the aircraft..."

8:50 a.m.: The military receives word that a plane has hit the World Trade Center. At the same time, American 77 ceases communication with air traffic controllers.

8:51 a.m.: The controller notices a change in the transponder code from United 175. The plane does not respond to repeated requests to change it back.

8:53 a.m.: Military fighter jets summoned for American 11 are airborne, but still lack a target and information about the threat. At the same time, the air traffic controller tells a peer there is a second hijacking and United 175 is unaccounted for. The controller begins diverting planes from the path of United 175.

8:54 a.m.: FAA Indianapolis air controllers notice American 77 deviating from its flight plan. The flight does not respond to contacts, and controllers are unaware of the hijacking and crash in New York.

8:56 a.m.: American 77 turns off its transponder.

9:00 a.m.: FAA Indianapolis notifies agencies that American 77 is missing, possibly crashed and seeks military help for a search and rescue.

9:01 a.m.: FAA New York Center notifies its command of its dilemma. "We have several situations going on here. It's escalating big, big time. We need to get the military involved with us."

9:02 a.m.: FAA New York Center asks New York's terminal approach for help in finding United 175.

Terminal: "I got somebody who keeps coasting, but it looks like he's going into one of the small airports down there. Got him just out of 9,500 -- 9,000 now."

Boston Center: "Do you know who he is?"

Terminal: "...We don't know who he is. We're just picking him up now."

Boston Center: "Heads up man, it looks like another one coming in."

9:03 a.m.: United Airlines Flight 175 crashes into the South Tower of the World Trade Center. FAA Boston Center deciphers the message from American 11, and realizes hijackers control more than one plane.

9:08 a.m. til 9:13 a.m.: Military fighters are in a holding pattern over Long Island's coast. NORAD decides to ask the FAA to enter New York airspace as a defensive move. "... If this stuff is gonna keep on going, we need to take those fighters, put 'em over Manhattan. That's the best play right now."

9:10 a.m.: American 77 enters FAA Washington Center space but goes undetected for 36 minutes as the FAA checks westerly points for the craft.

9:09 a.m.: Fighter jets in Langley, Virginia, move to battle stations to backup New York fighters who may get low on fuel.

9:17 a.m.: The Federal Aviation Administration shuts down all New York City area airports.

9:20 a.m.: FAA Indianapolis learns about the other hijackings and becomes suspicious about American 77.

9:21 a.m.: The Port Authority of New York and New Jersey orders all bridges and tunnels in the New York area closed, and FAA Command Center tells Dulles terminal to look for targets.

9:25 a.m.: The military establishes a combat air patrol over Manhattan, and the FAA issues a nationwide ground stop of all aircraft.

9:28 a.m.: The FAA receives its last normal communication from United 93.

9:29 a.m.: FAA Cleveland Control Center hears screams and struggles from an unknown source and someone yelling, "Get out of here! Get out of here!" The control center notices United 93 has dropped 700 feet.

9:30 a.m.: President Bush, speaking in Sarasota, Florida, says the country has suffered an "apparent terrorist attack." Cleveland Center polls other flights to determine if they heard the screaming at 9:29. Several report they did.

9:32 a.m.: Dulles terminal spots a suspicious aircraft and notifies the Secret Service. An unarmed National Guard cargo plane begins following American 77. Cleveland Center receives another transmission on the frequency from where there was screaming. "Keep remaining sitting. We have a bomb on board."

9:34 a.m.: FAA notified that United 93 might have a bomb on board. Until 10:08, Cleveland Center provides FAA updates on United 93's course.

9:36 a.m.: NORAD learns of a suspicious aircraft a few miles from the White House and orders the Langley fighter jets back to Washington. Cleveland Center asks whether anyone has requested military interception of United 93.

9:38 a.m.: American 77, with 58 passengers, four flight attendants and two pilots, crashes into the Pentagon, the National Guard pilot reports the crash to Washington's terminal facility. The Langley jets are 150 miles away.

9:39 a.m.: A radio transmission from United 93 crosses. It is the voice of hijacker Ziad Jarrah: "Uh, is the captain. Would like you all to remain seated. There is a bomb on board and are going back to the airport."

9:41 a.m.: FAA Cleveland Center loses United 93's transponder signal, but uses visual sightings from other planes to track its turn east, then south.

9:42 a.m.: FAA Command Center learns from television reports that a plane has struck the Pentagon. The FAA orders all airborne craft to land at the nearest airport.

9:46 a.m.: Command Center notifies FAA headquarters that United 93 was 29 minutes away from Washington, D.C.

9:49 a.m.: FAA Command Center addresses Cleveland's 9:36 request to seek military intervention of United 93.

Command Center: "Uh, do we want to think about, uh, scrambling aircraft?"

FAA Headquarters: "Uh, God, I don't know."

Command Center: "Uh, that's a decision somebody's gonna have to make probably in the next 10 minutes."

10:01 a.m.: Command Center tell FAA headquarters that another aircraft had seen United 93 "waving his wings." It's believed to be evidence of the passengers' efforts to overpower the hijackers.

10:03 a.m.: United Airlines Flight 93, en route from Newark, N.J., to San Francisco with 38 passengers, two pilots and five flight attendants aboard, crashes about 60 miles southeast of Pittsburgh.

10:05 a.m.: The south tower of the World Trade Center collapses.

10:10 a.m.: Part of the Pentagon collapses.

10:13 a.m.: The 39-story United Nations building is evacuated. A total of 11,700 people were evacuated "as a precautionary measure," a U.N. spokeswoman said.

10:24 a.m.: The FAA announces that all inbound trans-Atlantic aircraft into the United States are being diverted to Canada.

10:28 a.m.: The World Trade Center's north tower collapses from the top down.

10:45 a.m.: All federal office buildings in Washington are evacuated.

10:52 a.m.: Washington-area airports have been closed, a Federal Aviation Administration spokeswoman says.

10:53 a.m.: New York's primary elections scheduled for today are postponed.

11:02 a.m.: New York City Mayor Rudy Giuliani orders the evacuation of the area south of the World Trade Center.

11:18 a.m.: American Airlines says it has lost two planes. The airline says American Flight 11, a Boeing 767, en route from Boston to Los Angeles, and Flight 77, a Boeing 757 flying from Dulles Airport to San Francisco, had crashed.

11:26 a.m.: United Airlines announces the crash of United Flight 93 southeast of Pittsburgh.

11:59 a.m.: United Airlines confirms that Flight 175 has crashed with 56 passengers and nine crew members aboard.

1:04 p.m.: Bush, speaking from Barksdale Air Force Base, La., says the U.S. military has been put on high alert worldwide. He asks for prayers for those killed or wounded in the attacks. "Make no mistake, the United States will hunt down and punish those responsible for these cowardly acts," he said.

1:48 p.m.: Bush leaves Barksdale aboard Air Force One and flies to Offutt Air Force Base in Omaha, Neb.

5:20 p.m.: World Trade Center Tower 7 collapses.*

6:41 p.m.: Defense Secretary Donald Rumsfeld holds a news conference at the Pentagon. Rumsfeld announces the Pentagon will reopen for business today.

6:54 p.m.: Bush returns to the White House from Omaha.

7:15 p.m.: In a White House briefing Attorney General John Ashcroft said, "We will not tolerate such acts." He said the government had set up a Web site for tips, ifccfbi.gov.

7:25 p.m.: The congressional leadership holds a briefing on the steps of the U.S. Capital. Senate plurality leader Tom Daschle, D-South Dakota says Congress will reconvene this morning.

8:30 p.m.: President Bush addresses the nation from the Oval Office.

Research Note: This revised (6-17-04) timeline has been compiled primarily from CNN reported testimony offered by Aviation and military officials at the 911 Commission Hearings.

Copyright Status: Public Domain.