United Airlines Flight 175

The flight was hijacked as part of the September 11 attacks. The team was assembled by al-Qaeda leader Osama bin Laden, who also provided the financial and logistical support, and was led by Khalid Sheikh Mohammed who devised the plot. Bin Laden and Mohammed, along with the hijackers, were motivated by anti-US sentiment. The attacks were given the go ahead by bin Laden in late 1998 or early 1999. The World Trade Center was chosen as one of the targets due to it being a prominent American symbol that represented economic prowess.[1]

The team of hijackers on United Airlines Flight 175 was led by Marwan al-Shehhi, originally from the United Arab Emirates with a stint in Hamburg, Germany as a student. By January 2001, the pilot hijackers had completed their training; Shehhi obtained a commercial pilot licence while training in South Florida,[1] along with American Airlines Flight 11 hijacker Mohamed Atta and Flight 93 hijacker Ziad Jarrah. The hijackers on Flight 175 included Fayez Banihammad, also from the UAE, and three Saudis: brothers Hamza al-Ghamdi and Ahmed al-Ghamdi, as well as Mohand al-Shehri.[2][3]

The hijackers were trained at an al-Qaeda camp called Mes Aynak in Kabul, Afghanistan, where they learned about weapons and explosives, followed by training in Karachi, Pakistan, where they learned about "Western culture and travel". Afterwards, they went to Kuala Lumpur, Malaysia for exercises in airport security and surveillance. Part of the training in Malaysia included boarding flights operated by US carriers so they could observe pre-boarding security screenings, flight crew movements around the cabin, and the timing of cabin services.[1][4]

A month before the attacks, Marwan al-Shehhi purchased two four-inch (10 cm) pocket knives from a Sports Authority store in Boynton Beach, Florida, while Banihammad bought a two-piece "snap" utility knife set at a Wal-Mart, and Hamza al-Ghamdi bought a Leatherman Wave multi-tool.[2][3] The hijackers arrived in Boston from Florida between September 7 and 9.[5]

Gate C19 at Boston's Logan International Airport was the boarding gate of United Flight 175 on September 11, 2001. An American flag was added to memorialize the site.

Hamza al-Ghamdi and Ahmed al-Ghamdi checked out of their hotel and called a taxi to take them to Logan International Airport in Boston, Massachusetts.[14] They arrived at the United Airlines counter in Terminal C at 06:20 Eastern Time and Ahmed al-Ghamdi checked two bags. Both hijackers indicated they wanted to purchase tickets, even though they already had paper tickets, which were purchased approximately 2 weeks before the attacks.[1] They had trouble answering the standard security questions, so the counter agent repeated the questions very slowly until satisfied with their responses.[3][15] Hijacker pilot Marwan al-Shehhi checked 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.[3] None of the Flight 175 hijackers were selected for extra scrutiny by the Computer Assisted Passenger Prescreening System (CAPPS).[16]

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 in seat 2B. At 07:27, Shehhi and Ahmed al-Ghamdi boarded and sat in business class seats 6C and 9D, respectively. One minute later, Hamza al-Ghamdi boarded and sat in 9C.[3][16]

The flight was scheduled to depart at 08:00 for Los Angeles. Fifty-one passengers and the five hijackers boarded the 767 through Terminal C's Gate 19. The plane pushed back at 07:58 and took off at 08:14 from Runway 9,[3][17] about the same time Flight 11 was hijacked. By 08:33, the aircraft reached cruising altitude of 31,000 feet (9,400 m), which is the point when cabin service would normally begin.[3] At 08:37, air traffic controllers asked the pilots of Flight 175 whether they could see American Airlines Flight 11. The crew first responded saying they could not locate the hijacked plane but would continue looking. They then responded that Flight 11 was at 29,000 feet (8,800 m), and controllers instructed Flight 175 to turn and avoid the aircraft.[18] The pilots declared that they had heard a suspicious transmission from Flight 11 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.[19][17]

Flight 175 was hijacked between 08:42 and 08:46, while Flight 11 was just minutes away from hitting the North Tower.[3] It is believed that hijackers Banihammad and al-Shehri forcibly entered the cockpit and attacked the pilots while the al-Ghamdis commanded passengers and crew to the aft of the cabin and al-Shehhi took over the controls.[17][20] Knives were used to stab the flight crew and kill both pilots.[1][17] One passenger also reported, during a phone call, the use of mace and bomb threats.[17] The first operational evidence that something was abnormal on Flight 175 came at 08:47, when the plane's transponder signal changed twice within the span of one minute, and the aircraft began deviating from its assigned course.[17][20] However, the air traffic controller in charge of the flight did not notice until minutes later at 08:51.[3] Unlike Flight 11, which had turned its transponder off, Flight 175's flight data could still be properly monitored.[20] 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.[3]

Around this time, the flight had a near midair collision with Delta Air Lines Flight 2315 flying from Hartford to Tampa, reportedly missing the plane by only 300 feet (90 m).[21][22] Dave Bottiglia, the controller who was working with the pilot of the Delta, yelled at the pilot to take evasive actions, adding "We have an airplane that we don't know what he's doing. Any action at all."[21][22] Moments before Flight 175 crashed, it avoided another near collision with Midwest Express Flight 7, which was flying from Milwaukee to New York.[23]

At 08:55 a supervisor at the New York Air Traffic Control Center notified the center's operations manager of the Flight 175 hijacking. Bottiglia – who was handling both Flight 11 and Flight 175 – remarked, "We might have a hijack over here, two of them."[3] At 08:58, Flight 175 was over New Jersey at 28,500 feet, heading toward New York City. In the five minutes from approximately 08:58 when Shehhi completed the final turn toward New York City until the moment of impact, the plane was in a sustained power dive, descending more than 24,000 feet in 5 minutes 4 seconds, at an average rate of over 5,000 feet per minute.[20] 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."[22]

Flight attendant Robert Fangman and passengers Peter Hanson and Brian David Sweeney made phone calls from GTE airphones in the rear of the aircraft. Airphone records also indicate that passenger Garnet Bailey made four phone call attempts to his wife.[24][25]

At 08:52, a male flight attendant – likely Fangman – called a United Airlines maintenance office in San Francisco and spoke with Marc Policastro.[17][26] Fangman reported the hijacking and said the hijackers were likely flying the plane. He also said both pilots were dead and that a flight attendant had been stabbed.[17] After a minute and 15 seconds, Fangman's call was disconnected.[24] Policastro subsequently made attempts to contact the aircraft's cockpit using the Aircraft Communication Addressing and Reporting System (ACARS) message system. He wrote, "I heard of a reported incident aboard your acft [aircraft]. Plz verify all is normal." He received no reply.[3]

Brian David Sweeney tried to call his wife, Julie, at 08:59, but ended up leaving a message, telling her the plane had been hijacked. He then called his parents at 09:00 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.[17] Sweeney said he thought the hijackers might come back, so he might have to hang up quickly. He then said goodbye to his mother as he quickly hung up.[27]

At 08:52, Peter Hanson called his father, Lee Hanson, in Easton, Connecticut, telling him of the hijacking. Hanson was traveling with his wife, Sue, and their two-year-old daughter, Christine, the youngest victim of the September 11 attacks. 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. Speaking softly, Hanson said the hijackers had commandeered the cockpit, a flight attendant had been stabbed, and that possibly someone else in the front of the aircraft had been killed. He also said the plane was flying erratically. Hanson asked his father to contact United Airlines, but Lee could not get through and instead called the police.[17][28]

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.[22]

As the call abruptly ended, Hanson's father heard a woman screaming.[22]

Diagram of the impact position of both aircraft

Diagram showing how debris from both aircraft fell after the impact

World Trade Center site with WTC 2

As the plane approached New York City, Shehhi would have seen the fire and smoke pouring from the North Tower in the distance.[29] The aircraft was in a banking left turn in its final moments, as it appeared the plane might have otherwise missed the building or merely scraped it with a wing. Therefore, those who were on the left side of the plane would also have had a clear view of the towers approaching, with one burning.[22] At 09:01, two minutes before impact as 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 Upper New York Bay in its final moments.[20]

Flight 175 explodes after hitting the South Tower.

At 09:03,[lower-alpha 1] Flight 175 crashed nose-first into the southern façade of the South Tower of the World Trade Center at over 500 miles per hour (800 km/h; 220 m/s; 430 kn),[lower-alpha 2] striking through floors 77 and 85[35][36] with approximately 9,100 U.S. gallons (34,000 L; 7,600 imp gal) of jet fuel on board.[37]

By the time Flight 175 struck the South Tower, multiple media organizations were already covering the crash of Flight 11, which had hit the North Tower 17 minutes earlier. The image of Flight 175's crash was thus caught on video from multiple vantage points on live television and amateur video, while approximately a hundred cameras captured Flight 175 in photographs before it crashed.[38] 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.[39]

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 (200 yd; 180 m) north of the former World Trade Center. Three floor beams of the top floor of the building were destroyed, causing major structural damage.[33][40][41][42]