map showing flight paths of four airliners that struck different targets
(Image by the U.S. Federal Bureau of Investigations)

By Laurie A. Shuster

On Sept. 11, 2001, al-Qaida terrorists boarded and hijacked four fully fueled passenger jets bound for cross-country trips and carried out coordinated homicidal attacks on New York City and Washington, D.C. Two planes struck the World Trade Center twin towers in New York, and one struck the Pentagon in northern Virginia, killing everyone aboard the planes as well as almost 3,000 people on the ground. The fourth plane crashed in a field near Shanksville, Pennsylvania, killing all on board. Below is an abbreviated timeline of the events (Eastern Daylight Time) as they unfolded that day, based on data from the FBI and

  • 7:59 a.m. – American Airlines Flight 11, a Boeing 767 with 92 people aboard, takes off from Boston’s Logan International Airport en route to Los Angeles.
  • 8:14 a.m. – United Airlines Flight 175, a Boeing 767 with 65 people aboard, takes off from Boston, also en route to Los Angeles.
  • 8:20 a.m. – American Airlines Flight 77 takes off from Dulles International Airport in northern Virginia (outside of Washington). The Boeing 757 is headed to Los Angeles with 64 people aboard.
  • 8:42 a.m. – United Airlines Flight 93, a Boeing 757 with 44 people aboard, takes off from New Jersey’s Newark International Airport en route to San Francisco.
  • 8:46 a.m. – The hijackers aboard Flight 11 crash the plane into floors 93-99 of the north tower of the WTC, killing everyone aboard and hundreds inside the building.
  • 8:47 a.m. – Within seconds, the New York Police Department and the Fire Department of New York dispatch units to the WTC, while police at the Port Authority of New York and New Jersey begin evacuating the north tower.
  • 8:50 a.m. – White House chief of staff Andrew Card alerts President George W. Bush that a plane has hit the WTC; the president is visiting an elementary school in Sarasota, Florida, at the time.
  • 9:03 a.m. – Hijackers crash United Airlines Flight 175 into floors 75-85 of the WTC’s south tower, killing everyone aboard and hundreds inside the building.
  • 9:08 a.m. – The Federal Aviation Administration bans all takeoffs of flights going to New York or through the airspace around the city.
  • 9:21 a.m. – The Port Authority closes all bridges and tunnels in the New York area.
  • 9:24 a.m. – The FAA notifies the North East Air Defense Sector of the U.S. Air Force about the suspected hijacking of Flight 77 after some passengers and crew aboard alert family members on the ground.
  • 9:31 a.m. – Speaking from Florida, Bush calls the events in New York an “apparent terrorist attack on our country.”
  • 9:37 a.m. – Hijackers aboard Flight 77 crash the plane into the western facade of the Pentagon in Washington, killing everyone aboard and 125 military and civilian personnel inside the building.
  • 9:59 a.m. – The south tower at the WTC collapses.
  • 10:03 a.m. – Flight 93 crashes into a field outside Shanksville, Pennsylvania, killing all aboard.
  • 10:28 a.m. – The north tower at the WTC collapses.
  • 2:51 p.m. – The U.S. Navy dispatches missile destroyers to New York and Washington.
  • 5:20 p.m. – The 47-story 7 WTC tower collapses after burning for hours; the building had been evacuated in the morning, and there are no casualties, though the collapse forces rescue workers to flee for their lives. It is the last of the WTC towers to fall.
  • 6:58 p.m. – Bush returns to the White House after stops at military bases in Louisiana and Nebraska.
  • 8:30 p.m. – Bush addresses the nation, calling the attacks “evil, despicable acts of terror” and declaring that America, its friends, and allies would “stand together to win the war against terrorism.”

Laurie A. Shuster is the editor in chief of Civil Engineering.

This article first appeared in the September/October 2021 issue of Civil Engineering as "The Events."


Read the next article in the collection: "The investigations: The World Trade Center towers."