The 9/11 Commission | The report that reconstructed the timeline of the attacks: 19 terrorists, 2,977 dead and a government that failed to piece together the facts

The attacks of Sept. 11, 2001, were four coordinated terrorist attacks, carried out by 19 members of Al Qaeda who hijacked commercial airliners to use them as weapons against symbolic targets of American power.

With 2,996 dead (including the 19 attackers) and more than 25,000 injured, it remains the deadliest terrorist attack in history and the deadliest incident ever for firefighters and police officers in U.S.

What happened that morning

The East Coast awoke to a mild, nearly cloudless morning. This is how the report commissioned by Congress to reconstruct the events describes it in its very first line. The 9/11 Commission Report reconstructs that morning using radar data, black boxes and in-flight calls—not the mythology that emerged after the attack. It establishes the sequence of the four flights and shows how the Federal Aviation Administration (FAA) and the North American Aerospace Defense Command (NORAD) pursued planes that no longer existed, while the FBI and the CIA had names of suspects and flight schools without having been able to connect the dots.

At Boston, Newark and Dulles, 19 men boarded four long-haul flights bound for California, fully fueled. By noon, the Twin Towers were gone, the Pentagon was ablaze and a Boeing 757 had crashed in a field in Pennsylvania.

At 8:14 a.m., routine communication was cut off. The commission places the hijacking at that time, over Massachusetts. Minutes later, flight attendant Betty Ong called the airline from an onboard phone. The cockpit was locked, and crew members had been injured. Amy Sweeney made another call and described the hijackers. At 8:24 a.m., by mistake, Atta broadcast over the control frequency: "We have some planes. Just stay quiet, and you'll be okay." The report uses that phrase as the title for the chapter covering that day.

At 8:46 a.m., the plane crashed into the north face of the North Tower, between the 93rd and 99th floors. No one on board survived. Inside the building, the impact sealed off the exits above the area where the plane struck.

At around 8:42:40 a.m., still under the control of its pilots, United Flight 175 notified air traffic control that it had heard a "suspicious transmission" from another aircraft. It was Mohamed Atta, on American Flight 11, speaking by mistake on the open frequency. Shortly thereafter, between 8:42 and 8:46 a.m., they hijacked Flight 175 over northwestern New Jersey. Whoever was already in the cockpit changed the transponder code: on ground monitors, the flight was no longer easy to track.

Passengers and crew members called their families and the airline. They reported that the cockpit had been taken over and that the plane was descending. At 9:03:11 a.m., Flight 175 crashed into the south face of the South Tower, between the 77th and 85th floors. An engine and other debris pierced the building and fell several blocks away. Cameras that had already been focused on the smoke from the North Tower captured the impact. Up until that moment, many people had been talking about an accident. The second plane put an end to that notion.

The Pentagon, 9:37 a.m.

American Airlines Flight 77 was a Boeing 757 bound for Los Angeles. It took off from Dulles Airport, near Washington, at 8:20 a.m. There were 58 passengers on board—five of whom were hijackers—and six crew members.

The commission places the hijacking between 8:51 and 8:54 a.m. The plane stopped responding, turned off its transponder and veered toward the capital. On the ground, for several minutes, air traffic controllers and military personnel were unsure exactly which aircraft it was or where it was headed. The report describes this gap in information bluntly: as Flight 77 approached the Potomac River, part of the system continued to search for a flight that no longer existed as such.

At 9:37:46 a.m., the plane crashed into the west facade of the Pentagon, the side that was under construction. The commission recorded the deaths of everyone on board and of 125 people in the building, including personnel from the Department of Defense and emergency responders. The impact tore a hole several stories high. The fire and the partial collapse of that section of the building complicated rescue efforts.

The flight that never reached its target

United Flight 93 was a Boeing 757 bound for San Francisco. It was scheduled to depart from Newark at 8 a.m.; it took off 42 minutes late, at 8:42 a.m. That delay, the commission says, changed the course of the day: by the time it was hijacked, the towers were already on fire and the Pentagon had been struck. It was piloted by Jason Dahl and LeRoy Homer. There were seven crew members and 37 passengers on board, four of whom were hijackers—not five, as on the other flights: Ziad Jarrah, the pilot; Ahmed al Haznawi; Ahmed al Nami and Saeed al Ghamdi.

The last routine communication was around 9:27 a.m. A minute later, over Ohio, screams were heard in the cabin. The commission places the hijacking at 9:28 a.m. The plane turns southeast, toward Washington. Jarrah, on the radio, says there is a bomb on board and asks the passengers to sit down.

Phone calls begin from the rear seats. Passengers Tom Burnett, Jeremy Glick, Mark Bingham, Todd Beamer and several others speak with family members and an operator. They are told about New York and the Pentagon. They agree to take action. The black box records the struggle, the "Let's roll!" attributed to Beamer and the moment they attempt to enter the cockpit.

At 10:03:11 a.m., Flight 93 crashes into a field near Shanksville, Pa., at full speed and upside down. No one on board survives. There were no other fatalities on the ground. The report concludes that the most likely target was the Capitol or the White House—Khalid Sheikh Mohammed pointed to the Capitol—and that the struggle prevented the plane from reaching its destination. It was the only one of the four that did not reach the city it was targeting.

New York collapses

At the World Trade Center, evacuation and rescue efforts intersected on the same stairwells. Those who could get down did so. Members of the New York Fire Department, Police Department and Port Authority were heading up, often without knowing which floors were off-limits. The report devotes an entire chapter to that morning in the towers: radios that couldn't communicate with each other, commanders who couldn't be heard on the upper floors and orders that didn't reach those already inside.

The North Tower, struck at 8:46 a.m. between floors 93 and 99, left those above the impact with no way out. The South Tower, struck at 9:03 a.m. lower down—between the 77th and 85th floors—collapsed first, at 9:59 a.m., 56 minutes after the crash. The North Tower held out until 10:28 a.m. In the afternoon, at 5:20 p.m., 7 World Trade Center collapsed, damaged by debris and fire. The commission describes how, on many upper floors, the only certainty was that there was no way down.

The official death toll for that day—the one used in the report and subsequent figures—is 2,977, excluding the 19 hijackers: 2,753 in New York, 184 at the Pentagon and 40 in Shanksville. It was the deadliest attack ever on U.S. soil. Deaths from illnesses among those who worked in the rubble came later and are not included in that Sept. 11 figure.