United Airlines flight 175

United Airlines flight 175, domestic passenger flight that was hijacked on the morning of September 11, 2001, as part of a coordinated terrorist attack on the United States by al-Qaeda. The plane was flown into the South Tower of the World Trade Center (WTC) in New York City. Shortly before, another hijacked plane, American Airlines flight 11, had flown into the North Tower of the WTC. The crashes and subsequent collapse of both towers resulted in the deaths of 2,753 people, per official records. It is the deadliest aviation disaster in history.

Timeline

Note: All times listed are Eastern Daylight Time.

• 8:14 AM: United Airlines flight 175 takes off from Boston, headed for Los Angeles. Aboard are 9 crew members and 56 passengers, including 5 hijackers.
• 8:42 AM: Flight 175 makes its last communication with air traffic controllers, reporting that during takeoff it heard a “suspicious transmission” from another airplane, later determined to be American Airlines flight 11. Around this time, flight 175 is hijacked, and some five minutes later its transponder code is changed.
• 8:46:40 AM: Hijackers on American Airlines flight 11 fly the airplane into the North Tower of the World Trade Center. The impact occurs between floors 93 and 99. Almost immediately emergency responders are sent to the building.
• 8:51 AM: Flight 175 changes from its assigned altitude, and repeated efforts by air traffic controllers to contact the plane are unsuccessful.
• 8:52 AM: A flight attendant calls United Airlines and informs officials that the plane has been hijacked and that both pilots are dead. During this time passengers are also phoning friends and family. Passenger calls will provide important information about the hijackings in subsequent investigations.
• 8:58 AM: Flight 175 sets a course for New York City.
• 9:00 AM: A passenger contacts his father for the second time that morning and reportedly tells him, “I think they intend to go to Chicago or someplace and fly into a building—Don’t worry, Dad—If it happens, it’ll be very fast.”
• 9:03:11 AM: Flight 175 crashes into the south Tower of the World Trade Center, striking between floors 77 and 85.
• 9:59 AM: The South Tower collapses.

Other hijacked planes

In addition to flights 175 and 11, two other planes were also hijacked on September 11, 2001: American Airlines flight 77 and United Airlines flight 93. Flight 77 departed from Dulles International Airport near Washington, D.C.,  and was headed for Los Angeles. Hijackers crashed the plane into the Pentagon in Virginia, killing 184 people. Flight 93 took off from Newark International Airport in New Jersey, with a destination of San Francisco. Following a vote, passengers rushed the cockpit in an attempt to retake the plane. As they started to breach the cockpit door, hijackers crashed the plane into a field near Shanksville, Pennsylvania. Forty people died.