United Airlines Flight 175

United Airlines Flight 175 was a scheduled U.S. domestic passenger flight from Logan International Airport in Boston, Massachusetts to Los Angeles International Airport, in California. On the morning of September 11, 2001, the flight was hijacked by five al-Qaeda-associated terrorists, and flown into the South Tower of the World Trade Center in New York City as part of the September 11 attacks. Approximately thirty minutes into the flight, the hijackers forcefully breached the cockpit, and overpowered the pilot and first officer, allowing lead hijacker and trained pilot Marwan al-Shehhi to take over the controls. The aircraft's transponder was turned off and the aircraft deviated from the assigned flight path for four minutes, before air traffic controllers noticed at 08:51. They made several unsuccessful attempts to contact the cockpit. Several passengers and crew aboard made phone calls from the plane and provided information about the hijackers and injuries to passengers and crew. The Boeing 767 operating as Flight 175 crashed into the South Tower of the World Trade Center at 09:03, killing all 65 people aboard, including the hijackers. The Flight 175 hijacking was coordinated with that of American Airlines Flight 11, which had struck the top of the North Tower 17 minutes earlier. The crash of Flight 175 into the South Tower was the only impact seen live on television around the world as it happened. It was upon the loss of Flight 175 that the world realized that the crashes of both aircraft at the World Trade Center were in fact deliberate. The impact and subsequent fire caused the South Tower to collapse, 56 minutes later, resulting in hundreds of additional casualties. During the recovery effort at the World Trade Center site, workers recovered and identified remains from Flight 175 victims (see the Aftermath section below), but many other body fragments could not be identified.

Background
The team of hijackers on United Airlines Flight 175 was led by Marwan al-Shehhi, from the United Arab Emirates. Shehhi obtained a commercial pilot's license while training in south Florida, training together with Flight 11 hijacker and plot coordinator, Mohamed Atta. The muscle hijackers on Flight 175 included Fayez Banihammad, from the UAE, and three Saudis: Hamza al-Ghamdi, Ahmed al-Ghamdi, and Mohand al-Shehri. On August 13, 2001, Marwan al-Shehhi purchased two four-inch pocket knives from a Sports Authority store in Boynton Beach, Florida, while Banihammad bought a two-piece snap knife set at a Wal-Mart, and Hamza al-Ghamdi bought a Leatherman Wave multi-tool. In early September 2001, the Flight 175 group of hijackers arrived in Boston from Florida. Hamza al-Ghamdi and Ahmed al-Ghamdi arrived together on September 7, and checked into the Charles Hotel in Cambridge, Massachusetts. The next day, they relocated to the Days Inn in Boston. Fayez Banihammad flew from Florida to Boston, together with Mohand al-Shehri, on September 8, and they checked into the Milner Hotel in Boston. Marwan al-Shehhi arrived in Boston on September 9, and stayed at the Milner Hotel where he shared a room with Mohamed Atta.

Flight
The United Airlines Flight 175 aircraft was a Boeing 767-222/ER built in 1983, registration number N612UA, with capacity of 168 passengers. It had 168 seats (10 in first class, 33 in business class, and 125 in economy class). On September 11, 2001, the flight carried only 56 passengers and 9 crew members, which represented a 33 percent load factor — well below the average load factor of 49 percent in the three months preceding September 11. The nine crew members included pilot Victor Saracini, First Officer Michael Horrocks, and flight attendants Robert Fangman, Amy Jarret, Amy King, Kathryn Laborie, Alfred Marchand, Michael Tarrou, and Alicia Titus.

Boarding
Upon checking out of the Days Hotel, a taxi was called to take Hamza al-Ghamdi and Ahmed al-Ghamdi to Logan International Airport. Ahmed al-Ghamdi and Hamza al-Ghamdi arrived at the United Airlines counter at 06:20 Eastern Time, with Ahmed al-Ghamdi checking in two bags. Both hijackers indicated they wanted to purchase tickets, though they already had paper tickets. They also had trouble answering the standard security questions, so the counter agent repeated the questions very slowly until the men gave the correct answer. Hijacker pilot Marwan al-Shehhi checked in a single bag at 06:45, and the other remaining hijackers, Fayez Banihammad and Mohand al-Shehri, checked in at 06:53. Banihammad checked two bags. None of the hijackers were selected for extra scrutiny by the Computer Assisted Passenger Prescreening System (CAPPS). Shehhi and the other hijackers boarded Flight 175 between 07:23 and 07:28. Banihammad boarded first and sat in first class seat 2A, while Mohand al-Shehri was seated in 2B. At 07:27, Shehhi and Ahmed al-Ghamdi boarded, and sat in business class seats 6C and 9D respectively. A minute later, Hamza al-Ghamdi boarded, and sat in 9C. The flight, which was scheduled to depart at 08:00, pushed back at 07:58 from Gate C19, and took off at 08:14 from runway 9, several minutes after Flight 11 departed. By 08:33, the aircraft reached cruising altitude of 31,000 feet, which is the point when cabin service would begin. At 08:37, air traffic controllers asked the pilots of Flight 175 whether they could see American Airlines Flight 11. The crew responded that the Flight 11 was at 29,000 feet, and controllers ordered Flight 175 to turn and avoid the aircraft. The pilots declared that they had heard a suspicious transmission upon takeoff. "Sounds like someone keyed the mic and said everyone stay in your seats," the flight crew reported. This was the last transmission from Flight 175.

Hijacking
The hijacking of Flight 175 occurred between 08:42 and 08:46. At 08:47, the plane's transponder signal changed once, and a second time within a minute, and the aircraft began deviating from its assigned course. But, the air traffic controller in charge of the flight did not notice until minutes later at 08:51. Unlike Flight 11, which had turned its transponder off, Flight 175's flight data could still be properly monitored. Also, at 08:51, Flight 175 changed altitude. Over the next three minutes, the controller made five unsuccessful attempts to contact Flight 175, and worked to move other aircraft in the vicinity away from Flight 175. At around this time, the flight had a near midair collision with Delta Air Lines Flight 2315, reportedly missing the plane by only 300 feet, as air traffic controller Dave Bottiglia frantically tried to tell the Delta pilot to take evasive action. Bottiglia was the first person in the control center to realize that Flight 175 was hijacked when he gave directions for a turn. Flight 175 did not respond, it instead accelerated and headed toward Delta Air Lines Flight 2315. The controller commanded the Delta pilot, "Take any evasive action necessary. We have an airplane that we don't know what he's doing. Any action at all." Moments before Flight 175 crashed, it avoided a near collision with Midwest Express Flight 7. At 08:55, a supervisor at the New York Air Traffic Control center notified the center's operations manager of the Flight 175 hijacking, and David Bottiglia, who was tracking Flight 175, noted, "we might have a hijack over here, two of them." By 08:58, the plane was heading toward New York and descended from an altitude of 28,500 feet over New Jersey. From the time, at approximately 08:58, when Shehhi completed the final turn toward New York City to the moment of impact, the plane went into a sustained power dive, descending more than 24,000 feet in 5 minutes 4 seconds, for an average rate of over 5,000 feet per minute. New York Center air traffic controller Dave Bottiglia reported he and his colleagues "were counting down the altitudes, and they were descending, right at the end, at 10,000 feet per minute. That is absolutely unheard of for a commercial jet."

Calls
Flight attendant Robert Fangman, as well as two passengers (Peter Hanson and Brian David Sweeney) made phone calls from United Airlines Flight 175, using GTE airphones, from the rear of the aircraft. Airphone records also indicate that Garnet Bailey made four phone call attempts, trying to reach his wife. Flight attendant Robert Fangman called a United Airlines office in San Francisco at 08:52, and spoke with Marc Policastro. Fangman reported the hijacking, and said that the hijackers were likely flying the plane. He also said that both pilots were dead, and that a flight attendant was stabbed. After a minute and 15 seconds, Fangman's call was disconnected. Policastro subsequently made attempts to contact the aircraft's cockpit using the Aircraft Communication Addressing and Reporting System (ACARS) message system. Brian David Sweeney tried calling his wife, Julie, at 08:58, but ended up leaving a message, telling her that the plane had been hijacked. He then called his parents at 9:00 a.m., and spoke with his mother, Louise. Sweeney told his mother about the hijacking, and mentioned that passengers were considering storming the cockpit and taking control of the aircraft, as the passengers aboard United Airlines Flight 93, which had not yet been hijacked, would. At 08:52, Peter Hanson called his father, Lee Hanson in Easton, Connecticut, telling him of the hijacking. The family was originally seated in Row 19, in seats C, D, and E, however Peter placed the call to his father from seat 30E. Hanson was traveling with his wife, Sue, and 2½ year old daughter, Christine. Speaking softly, Hanson said that the hijackers had commandeered the cockpit, that a flight attendant had been stabbed, and possibly someone else in the front of the aircraft had been killed. He also said that the plane was flying erratically. Hanson asked his father to contact United Airlines, but Lee could not get through and instead called the police. Peter Hanson made a second phone call to his father at 09:00: It's getting bad, Dad. A stewardess was stabbed. They seem to have knives and Mace. They said they have a bomb. It's getting very bad on the plane. Passengers are throwing up and getting sick. The plane is making jerky movements. I don't think the pilot is flying the plane. I think we are going down. 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....Oh my God... oh my God, oh my God." As the call abruptly ended, Hanson's father heard a woman screaming.

Crash
At 09:01, two minutes before impact as United Airlines Flight 175 continued its descent into Lower Manhattan, the New York Center alerted another nearby Air Traffic Facility responsible for low flying aircraft, which was able to monitor the aircraft's path over New Jersey, and then over Staten Island and New York Harbor in its final moments. Flight 175 crashed into the southern facade of Tower 2 of the World Trade Center (south tower) at 9:03:04, traveling at approximately 545 mph and impacting between floors 77 and 85 with approximately 10,000 gallons of jet fuel. Onboard were 56 passengers (including the 5 hijackers) and 9 crew members, none of whom survived. The youngest person on Flight 175 was 2½-year-old Christine Hanson of Groton, Massachusetts, and the oldest was 80-year-old Dorothy DeAurajo of Long Beach, California. Hundreds more were killed within the tower and from its ensuing explosion, fires, and eventual collapse. Around 637 people were killed instantly or trapped at and above the floors of impact in the South Tower. According to eyewitnesses and video footage, the aircraft appeared to execute a banking left turn in the final moments, as it appeared that the plane might have otherwise missed the building or merely scraped it with its wing. Upon crashing, the plane was banked left. Those seated on the left side of the plane would, therefore, have had a clear view of the towers approaching, with one burning, until the final moment of the flight. The image of the crash was caught on video from multiple vantage points on live television and amateur video, while approximately 100 cameras captured Flight 175 in photographs before it crashed. Video footage of the crash was replayed numerous times in news broadcasts on the day of the attacks, and in the following days, before major news networks put restrictions on use of the footage. After the plane penetrated through the tower, part of the plane's landing gear and fuselage came out the north side of the tower and crashed through the roof and two of the floors of 45–47 Park Place, between West Broadway and Church Street, (600 feet (180 meters)) north of the former World Trade Center. The plane parts destroyed three floor beams, and severely compromised the building's internal structure. Nine years later the building was part of a national controversy as the result of efforts to build a Muslim center and mosque near the site.

Collapse
Unlike at the North Tower, initially, one of the three stairwells was still intact after Flight 175 crashed into the South Tower. This was because the plane struck the tower from an angle, and not straight on like Flight 11 in the North Tower had done. Only 18 people passed the impact zone through the available stairway and left the South Tower safely before it collapsed. One of them, Stanley Praimnath, was on the 81st floor and witnessed Flight 175 coming toward him. One of the wings ended up in his office. Some people above the impact zone made their way upward toward the roof in hopes of a helicopter rescue. However, access doors to the roof were locked. In any case, thick smoke and intense heat prevented rescue helicopters from landing. The South Tower collapsed at 9:59:02 after burning for 56 minutes.

Aftermath
Some debris from the aircraft were recovered nearby, including landing gear found on top of a building on the corner of West Broadway and Park Place, an engine found at Church & Murray Street, and a section of the fuselage landed on top of 5 World Trade Center. During the recovery process, small fragments were identified from some passengers on Flight 175, including a six-inch piece of bone belonging to Peter Hanson, and small bone fragments of Lisa Frost. Remains of many others aboard Flight 175 were never recovered. Shortly after the crash by the terrorists, the flight number for future flights on the same route was changed from Flight 175 to Flight 1525 "out of respect for those who died in the attack". Since then, United Airlines has renumbered and rescheduled all flights from Boston to Los Angeles, and none of its morning flights depart at 8:00 AM EDT. As of September 2007, this flight has now been redesignated as Flight 163 and Flight 168, which both operate using a Boeing 757-200.