Air traffic control during the September 11 attacks

Air traffic control, in particular those of Newark Liberty International Airport and NORAD, played a major role in maintaining order and grounding flights during the September 11 attacks. Controllers made contact with all four hijacked aircraft prior to the attacks, and two made contact with the hijackers themselves.

Air traffic controllers at the Washington Air Traffic Control Center.

National Air Traffic Controllers Association described the day as "the single greatest feat in all of ATC history".

Communications with hijacked flights

American Airlines Flight 11

A Boston TRACON air traffic controller communicated with American Airlines Flight 11 until 8:13:52, when last known contact with the aircraft was made prior to it being hijacked. The controller told the flight to "climb, maintain flight level three five zero" two times, although it never complied with the order.^[1] The Boston Center later made contact with the Cleveland Center, noting that "we don’t know where he is going …" and that the plane was at an unknown altitude.^[2]

At 8:24, Joseph Cooper, a FAA controller in Boston, heard Mohamed Atta say "We have some planes." By 8:38, three Northeast Air Defense Sector identification technicians were communicating with a military operations specialist at the FAA in Boston. The group was trying to figure out where the plane was going.^[3] At 8:46:40, Flight 11 crashed into the North Tower.^[4] The FAA confirmed that Mohamed Atta (his name wasn't known at that time) said "planes", instead of just "plane" around 9:06. The FAA's Indianapolis Center’s Operations Manager was told that Flight 11 was hijacked at 9:11 by an American Airlines dispatcher.^[3]

United Airlines Flight 175

Controller Greg Taccini worked with United Airlines Flight 175 prior to its hijacking; the same New York Air Route Traffic Control Center controller who had worked the airspace that American Airlines Flight 11 was in also briefly made contact with Flight 175 prior to the hijacking.^[4] At 8:46 a.m., the pilot of Flight 175 made a report that a "suspicious transmission" had came from another aircraft on their frequency; the transmission was later attributed to the hijackers of Flight 11. This transmission was the last verifiable contact the flight had with ground control before it was hijacked a few moments later.^[4]

New York Center and New York TRACON operators reacting to United Airlines Flight 175 impacting the South Tower of the World Trade Center

At 8:51:43 the aircraft was told by the New York Center to recycle its transponder;^[5] it never complied. At this point in the flight air traffic controllers were repeatedly attempting to make contact with the aircraft, although the flight had been hijacked by then.^[4] At 9:02, controllers observe the plane crash into the South Tower over the next minute.^[3]

American Airlines Flight 77

The air traffic controllers in Indianapolis receive their last routine communication from American Airlines Flight 77 at 8:51, the aircraft pulls its transponder and deviating from its path 3 minutes later. By 9:10, Flight 77 appeared on Washington D.C's radar. The air traffic controllers realized Flight 77 was hijacked around 9:20.^{[citation needed]} At 9:32, air traffic controllers at the Dulles Terminal Radar Approach Control saw Flight 77 "tracking eastbound at a high rate of speed.”^[6] At 9:37:46, Flight 77 crashed into the western side of The Pentagon at a speed of around 530 miles per hour.^[7] Everyone in the aircraft and 125 people in the building were killed.^[7]

United Airlines Flight 93

At 9:27, the last transmission was made with a Cleveland Air Traffic Controller,^{[citation needed]} in which a struggle was recorded.^[3] At 9:41, the transponder was pulled and the aircraft turned towards Washington D.C.. The Cleveland Center tracked the plane until it crashed in Shanksville, Pennsylvania, after the passengers retook the aircraft.^{[citation needed]}

Grounding and diverting flights following the nationwide grounding order

McCormick was informed of the hijackers on American Airlines Flight 11 at 8:42 a.m. McCormick originally thought that the plane was going for a landing in Newark airport. After reaching a controller in Newark, McCormick instructed him to look to see if he was landing. The controller then informed McCormick that the plane hit the North Tower. In an interview, McCormick stated that in that moment he recalled upon the 1993 World Trade Center bombing and then realized that the plane crashing into the North Tower was an act of terrorism. In response to his revelation, McCormick went to the person who had the job of coordination between air traffic control and military operations and told them "to scramble. Get ahold of northeast air defense and scramble."^[8]

At 9:04 Ben Sliney issued a "ground stop," which banned planes from taking off. Shortly after, McCormick ordered the shutdown of the airspace, known as an "ATC Zero".^{[citation needed]}

After the two planes hit the towers, the air traffic controllers had to ground all of the planes.^[9] Sources conflict on whether 5,050 planes or 4,000 planes were grounded.^[10][9]

Reactions

In 2011, the Federal Aviation Administration released a video commending the efforts of the air traffic controllers during 9/11.^[11]

The Reporters Committee for the Freedom of the Press has criticized the Federal Aviation Administration for destroying a tape of statements by the New York air traffic controllers after the September 11th attacks. On September 11, 2001 at 11:40 a.m., 6 air traffic controllers were brought into a conference room reportedly known as the “Bat Cave.” The air traffic controllers had just tracked down the hijacked planes. Due to concerns about stress making the controllers unable to produce written statements, each of the 6 people gave a recorded statement that was around 5 to 10 minutes long. All of the statements were combined into a single videotape, which was to be deleted after each video statement was turned into written ones. A few months after the tape was made, a quality-assurance manager destroyed the tape without direction. The quality-assurance manager stated they felt strongly that the tape shouldn't have been made due to the air traffic controllers not being “in the correct frame of mind”.^[12] The Department of Transportation issued a report after then Senator McCain alleged that a audiotape was destroyed.^[13]

See also

• Communication during the September 11 attacks