United Airlines Flight 175

United Airlines Flight 175 was a scheduled domestic passenger flight from Logan International Airport, in Boston, Massachusetts, to Los Angeles International Airport, in Los Angeles, California. On September 11, 2001, the Boeing 767-200 operating the route was hijacked by five al-Qaeda terrorists and was deliberately crashed into the South Tower of the World Trade Center in New York City, killing all 65 people aboard and an unconfirmed number in the building's impact zone.

Approximately thirty minutes into the flight, the hijackers forcibly breached the cockpit and overpowered the pilot and first officer, allowing lead hijacker and trained pilot Marwan al-Shehhi to take over the controls. Unlike Flight 11, whose transponder was turned off, Flight 175's transponder was visible on New York Center's radar, which depicted the aircraft's deviation from its assigned flight path for four minutes before air traffic controllers took notice at 08:51 EDT. Thereafter, they made several unsuccessful attempts to contact the cockpit. Unbeknownst to the hijackers, several passengers and crew aboard made phone calls to family members and relayed information regarding the hijackers and casualties suffered by passengers and crew.

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