It was 7.45am at Logan airport in Boston and ground control was going through the perfunctory business of talking the pilot of American Airlines flight 11 through the manoeuvres towards takeoff.
Sixty-seven minutes later, with the jargon silenced, the plane was slammed into the north tower of the World Trade Centre, the first calamity in a chain that would leave more than 5,500 dead in the US.
Five weeks after the attacks, transcripts of what went on between the pilots of the hijacked planes and air traffic controllers trace the air paths from banality to doom.
At 8.14am two controllers are recorded discussing the fact that the pilot is out of contact. There is silence for 10 minutes until a hijacker's voice is heard. "We have some planes," it says. "Just stay quiet and you will be OK. We are returning to the airport."
A controller asks "Who's trying to call me?" and one minute later air traffic control centres are told that a plane has been hijacked. Then silence.
Transcripts of words carried on the frequency used by pilots and air traffic controllers on the two planes that hit the World Trade Centre and the one flown into the Pentagon were obtained by the New York Times.
The newspaper also discloses that a military cargo plane was asked to identify the Boeing that crashed into the Pentagon two minutes before it did so and that three National Guard F-16s might have had time to shoot down flight 93 before it reached its target had it not crashed.
On United Airlines flight 175 at 8.37am, with no reason to suspect that 26 minutes later he and the other 64 innocent people on board would be dead after being used as a projectile against the south tower, the pilot receives a message from ground control asking him to look for the silent flight 11.
Ninety seconds before his plane was taken over by the hijackers the pilot betrays his unease. "We heard a suspicious transmission on our departure out of Boston," he says. "Someone keyed the mike and said 'Everyone stay in your seats. " Silence again.
At 8.53am another controller realises what is going on: "We may have a hijack."
The first indication that something is wrong with American flight 77 comes nine minutes after the trade centre was attacked, when a controller in Indianapolis is unable to make contact with the pilot. He never does again and 42 minutes later the Boeing 757 with six crew and 58 passengers crashes into the Pentagon.
American Flight 11
Boston to Los Angeles (crashed into north tower of World Trade Centre)
8.00 Plane takes off from Logan international airport, Boston.
8.13 Boston control centre: "AAL11 turn 20 degrees right."
Pilot of AAL11: "20 right AAL11."
Controller: "AAL11 now climb maintain FL350 [35,000 feet]."
Controller: "AAL11 climb maintain FL350."
Controller: "AAL11 Boston."
8.14:33 Controller A: "AAL11 ah the American on the frequency how do you hear me?"
Controller B breaks in: "This is Athens."
A: "This is Boston. I turned American 20 left and I was going to climb him. He will not respond to me now at all."
B: "Looks like he's turning right."
A: "Yeah, I turned him right."
B: "Oh, OK."
A: "And he's only going to um I think 29."
B: "Sure that's fine."
A: "Eh, but I'm not talking to him."
B: "He won't answer you. He's nordo [no radar] roger. Thanks."
8.24:38 Hijackers' voices heard: "We have some planes. Just stay quiet and you will be OK. We are returning to the airport. Nobody move, everything will be OK. If you try to make any moves you'll endanger yourself and the airplane. Just stay quiet."
8.25:00 The control tower notifies several air traffic control centres that a hijack is taking place.
8.33:59 Hijackers' voices heard: "Nobody move, please, we are going back to the airport. Don't try to make any stupid moves."
8.47:00 Plane crashes into the north tower of the World Trade Centre
United Flight 175
Boston to Los Angeles
(crashed into south tower of World Trade Centre)
8.14 Plane takes off from Logan international airport
8.31:04 Flight makes contact with Boston control centre.
8.37:08 Controller asks pilots to look for a lost American Airlines plane: "Do you have traffic look at uh your 12 to 1o'clock at about, uh, 10 miles southbound to see if you can see an American seventy six seven out there please."
UAL175: "Affirmative we have him, uh, he looks, uh, about 20, yeah, about 29, 28,000."
Controller: "United 175, turn five, turn 30 degrees to the right. I [want to] keep you away from this traffic."
8.41:32 Cockpit: "We figured we'd wait to go to your centre. We heard a suspicious transmission on our departure out of Boston. Someone keyed the mike and said: 'Everyone stay in your seats.' It cut out."
Flight transmits "Did you copy that?" (controller on land line).
Flight turns towards the south-west with ATC clearance.
8.46:18 Transponder signal no longer received.
8.53:23 Controller: "We may have a hijack. We have some problems over here right now."
9.00:00 Last radar reading is seen at an altitude of 18,000 feet as flight is descending at a ground speed of 480 knots.
9.03 Plane crashes into south tower of World Trade Centre
American Flight 77
Washington to Los Angeles (crashed into Pentagon)
The plane takes off from Dulles airport at 8.20am and climbs to 35,000 feet. At 8.50:51 there is the last radio communication with aircraft and six minutes later transponder contact is lost.
Air traffic controllers try to make contact but fail. At 9.25 the controller observes the plane moving towards Washington. Eight minutes later, the US secret service is informed and the aircraft is observed completing a right 360-degree turn, just south of the Pentagon. At 9.36 the national airport instructs a military C130 (Golfer 06) that has just departed Andrews air force base to intercept the flight and identify it. At 9.38 AA77 crashes into the south-west side of the Pentagon
United Flight 93
Newark to San Francisco (crashed in Shanksville, Pennsylvania)
The plane takes off from Newark at 8.42am. At 9.28 there are the first audible signs of problems, in background cockpit noise. Seven minutes later, the plane climbs without authorisation, before, at 9.36.31, turning off course.
During this time, two passengers make calls to their wives saying passengers are discussing how to stop hijackers; and a struggle - recorded by the cockpit voice recorder - occurs. At 10.00 the controller observes the plane is flying at 7,500 feet. Six minutes later the controller says the flight is down