On Sept. 11, 2001, United Airlines Flight 93 left Newark, N.J., at 8:42 a.m., heading for San Francisco, Calif. There were 38 passengers and a crew of seven on board. About 80 minutes later, the plane crashed into a field in Pennsylvania.
8:42 a.m. United 93 took off from Newark, more than 40 minutes late.
9:28 United 93 acknowledged a transmission from an FAA center controller. This was the last normal contact the FAA had with United 93.
9:29 A Cleveland Center controller and pilots of aircraft in the vicinity heard "a radio transmission of unintelligible sounds of possible screaming or a struggle from an unknown origin…" The controller responded, seconds later: "Somebody call Cleveland?"
This was followed by a second radio transmission, with sounds of screaming and someone yelling "Get out of here, get out of here," again from an unknown source.
The Cleveland Center controller began to try to identify the possible source of the transmissions, and noticed that United 93 had descended some 700 feet. The controller attempted to raise United 93 several times, with no response.
9:30 The controller began to poll the other flights on his frequency to determine if they heard the screaming; several said they had.
9:32 A third radio transmission came over the frequency: "Keep remaining sitting. We have a bomb on board."
The controller understood, but chose to respond: "Calling Cleveland center, you're unreadable. Say again, slowly."
He notified his supervisor, who passed the notice up the chain of command.
9:34 Cleveland Center reported, "United 93 may have a bomb on board," to the FAA Command Center at Herndon, Va.; the information was relayed to the FAA headquarters.
By this time, two of the four hijacked planes had crashed. FAA headquarters had established an open line of communication with the FAA Command Center at Herndon, Va., and instructed it to poll all the centers about suspect aircraft. The Command Center executed the request. For the next 30 minutes, a Command Center manager updated executives at FAA headquarters on the progress of United 93. During this time, the plane reversed course over Ohio and headed toward Washington, D.C.
The Cleveland controller had also observed United 93 climbing to 40,700 feet and immediately moved several aircraft out of its way. The controller continued to try to contact United 93, and asked whether the pilot could confirm that he had been hijacked. There was no response.
9:36 Cleveland Center asked Command Center specifically whether someone had requested the military to launch fighter aircraft to intercept United 93. Cleveland Center offered to contact a nearby military base. Command Center replied that FAA personnel well above them in the chain of command had to make that decision and were working the issue.
9:39 A fifth radio transmission came over the radio frequency from United 93:
Ziad Jarrah: Uh, is the captain. Would like you all to remain seated. There is a bomb on board and are going back to the airport, and to have our demands [unintelligible]. Please remain quiet.
The controller responded: "United 93, understand you have a bomb on board. Go ahead." The flight did not respond.
9:41 Cleveland Center lost United 93's transponder signal. The controller located the aircraft on primary radar, matched its position with visual sightings from other aircraft, and tracked the flight as it turned east, then south.
9:42 Command Center learned from television news reports that a plane had struck the Pentagon. The Command Center’s national operations manager, Ben Sliney, ordered all FAA facilities to instruct all airborne aircraft to land at the nearest airport.
This was a totally unprecedented order. The air traffic control system handled it with great skill, as about 4,500 commercial and general aviation aircraft soon landed without incident.
9:46 Command Center updated FAA headquarters that United 93 was now "29 minutes out of Washington, D.C."
9:49 Thirteen minutes after getting the question from Cleveland Center about military help, Command Center suggested that someone at headquarters should decide whether to request military assistance:
FAA Headquarters: They're pulling Jeff away to go talk about United 93.
Command Center: Uh, do we want to think about, uh, scrambling aircraft?
FAA Headquarters: Uh, God, I don't know.
Command Center: Uh, that's a decision somebody's gonna have to make probably in the next 10 minutes.
FAA Headquarters: Uh, ya know everybody just left the room.
9:53 FAA headquarters informed Command Center that the deputy director for air traffic services was talking to Deputy Administrator Monte Belger about scrambling aircraft. Then Command Center informed headquarters they lost track of United 93 over the Pittsburgh area. Within seconds, Command Center received a visual report from another aircraft, and informed headquarters that the aircraft was 20 miles northwest of Johnstown. A second aircraft had also spotted United 193.
10:01 Command Center advised FAA headquarters that one of the aircraft had seen United 93 "waving his wings." The aircraft had witnessed the radical gyrations in what investigators believe was the hijackers’ effort to defeat the passenger assault.
10:03:11 United 93 crashed in a field near Johnstown, Pa., 125 miles from Washington, D.C.
10:07 The military's NEADS (the Northeast Air Defense Sector) received a call about United 93 from the military liaison at Cleveland Center. The center was unaware that the aircraft had already crashed.
10:08 Five minutes later, Command Center forwarded this update to headquarters:
Command Center: OK. Uh, there is now on that United 93.
FAA Headquarters: Yes.
Command Center: There is a report of black smoke in the last position I gave you, 15 miles south of Johnstown.
FAA Headquarters: From the airplane or from the ground?
Command Center: Uh, they're speculating it's from the aircraft.
FAA Headquarters: OK.
Command Center: Uh, who, it hit the ground. That's what they’re speculating, that's speculation only.
The aircraft that spotted the "black smoke" was an unarmed Air National Guard cargo plane that also had seen American 77 crash into the Pentagon 26 minutes earlier. After being diverted to track American 77, the cargo plane had resumed its flight to Minnesota and saw the smoke from the crash of United 93, less than two minutes after the plane went down.
10:10 Having no knowledge either that United 93 had been heading toward Washington, D.C., or that it had crashed, the NEADS Mission Crew Commander explicitly instructed that the Langley Air Force Base fighters that had been deployed did not have "clearance
to shoot" aircraft over the nation's capital.
The news of a reported bomb on board United 93 spread quickly at NEADS. The air defenders searched for United 93's primary radar return and tried to locate fighters to scramble toward the plane.
10:15 NEADS called Washington Center to report:
NEADS: I also want to give you a heads-up, Washington.
FAA (DC): Go ahead.
NEADS: United nine three, have you got information on that yet?
FAA: Yeah, he's down.
NEADS: He's down?
FAA: Yes.
NEADS: When did he land? Cause we have got confirmation...
FAA: He did not land.
NEADS: Oh, he's down? Down?
FAA: Yes. Somewhere up northeast of Camp David.
NEADS: Northeast of Camp David.
FAA: That's the last report. They don't know exactly where.
The NEADS air defenders never located the flight or followed it on their radar scopes. The flight had already crashed by the time they learned it was hijacked.
10:17 Command Center advised headquarters of its conclusion that United 93 had indeed crashed.
Despite the discussions about military assistance, no one from FAA headquarters requested military assistance regarding United 93. Nor did any manager at FAA headquarters pass any of the information it had about United 93 to the military.
Copyright 2022 NPR. To see more, visit https://www.npr.org.
