An American Airlines pilot stayed at the helm of hijacked Flight 11 much of the way from Boston to New York, sending surreptitious radio transmissions to authorities on the ground as he flew.
Because the pilot's voice was seldom heard in these covert transmissions, it was not clear to the listening air-traffic controllers which of the two pilots was flying the Boeing 767. What is clear is that the pilot was secretly trying to convey to authorities the flight's desperate situation, according to controllers familiar with the tense minutes after Flight 11 was hijacked.
The pilot was apparently triggering a "push-to-talk button" on the aircraft's yoke, or "wheel" - a feature that enables pilots to have their hands on the controls while communicating, the controllers say. By doing so, the pilot gave controllers a way to hear much of what was said and other noises in the cockpit. His ability to do so also indicates that he was in the driver's seat much of the way to the plane's fiery rendezvous with the World Trade Center.
"The button was being pushed intermittently most of the way to New York," a controller told the Monitor. "He wanted us to know something was wrong. When he pushed the button and the terrorist spoke, we knew. There was this voice that was theatening the pilot, and it was clearly threatening."
During these transmissions, the pilot's voice and the heavily accented voice of a hijacker were clearly audible. At other times, the transmission was clear, but exactly what was happening in the cockpit was confused.
All of it was recorded by a Federal Aviation Administration traffic-control center. Those tapes are now presumed to be in the hands of federal law-enforcement officials, who arrived at the flight-contol facility minutes after Flight 11 crashed into the World Trade Center. The tapes presumably could provide clues about the hijackers - and may become even more important if the plane's "black boxes" are damaged or never found.
Even before those messages were received, though, and even before Flight 11 veered sharply toward New York City from its scheduled path, air-traffic controllers knew something was wrong. They just didn't know how wrong.
Flight 11 departed Boston's Logan International Airport about 7:59 a.m. Tuesday, destined for Los Angeles. A course for the aircraft had been charted and instructions given to its pilots, air-traffic controllers say.
The flight's handler was sitting in a windowless concrete bunker in Nashua, N.H., - one of 20 FAA centers that handle long-distance traffic once aircraft have left airport airspace, the controllers say. As he gave instructions to several aircraft, the controller was watching the 27-inch, high-resolution Sony TV consoles in the recently updated FAA facility. The screen displayed Flight 11's key information, including its altitude, direction, and identifying number. The controller had just given the plane, now about 15 to 20 minutes due west of Logan and cruising above western Massachusetts, permission to climb from 29,000 feet to 31,000 feet.
But nothing happened.
"He was cleared to continue his climb and he did not," a controller says. "He was given permission to turn to go around [other airplane] traffic at 29,000 [feet]. So he [the controller handling the plane] issued a further climb, and [the plane] does not respond. That was the first indication we had of a problem."
The controller handling the plane then repeatedly tried to contact Flight 11 on the regular frequency, according to two other controllers. Getting no response, the controller went to an emergency frequency.
"They were trying to raise the aircraft, trying to raise the aircraft, and they can't," says a colleague. "So they call them on the 121.5 emergency frequency."
"American 11, this is Boston Center, how do you read?" was repeated several times with no response, a controller says. But because aircraft sometimes lose radio contact with their controllers, he was not unduly concerned.
Just then, however, controllers noticed something more worrisome.
Flight 11's transponder had stopped working. It was no longer sending a radar pulse. The plane's altitude also became a matter of guesswork for controllers, though the Boeing 767 was still visible on radar. Still, the controllers hoped that the plane simply had an electrical problem.
"Then the plane turned [south toward New York], and then they heard the transmission with the terrorist in the background," the controller says. "The voice upset him [the controller] because he knew right then that he was working a hijack. Several other people heard the voice, and they could tell by the sound of it, intuitively, that this was a bad situation."
Another controller at the Nashua center confirms these events, adding some of what the hijacker was saying. "One of the pilots keyed their mike so the conversation between the pilot and the person in the cockpit could be heard," a second controller says. "The person in the cockpit was speaking in English. He was saying something like, 'Don't do anything foolish. You're not going to get hurt.' "
This controller also says that someone in the cockpit may have said something about guiding the plane toward Kennedy or LaGuardia airport in New York. But the controller, who was not handling the plane himself, is unsure whether the pilot or hijacker was speaking. If the latter, it may have been a ruse to make the pilot believe the plane was being diverted to an airport, not to a murder-suicide mission at the World Trade Center.
Not understood by controllers at the time, one of them says, was an ominous statement by the hijacker that sounded something like: "We have more planes. We have other planes."
The controller speculates that the hijacker may have deliberately deactivated the plane's transponder to keep the pilot from notifying the ground of a hijack. The Nashua facility never received a special four-digit emergency code a pilot would ordinarily send at the faintest whiff of a hijack situation. But the controllers already knew a hijack was in progress because of the pilot's radio transmission.
The other controller also speculates that anyone knowledgeable enough to cut off the transponder might also have pulled the circuit breaker for the cockpit voice recorder in the so-called black box, deactivating it, to minimize information available to authorities.
At about 8:28 a.m., the controller handling the plane and back-up support watched the jet's radar signal turn over eastern New York and head south along the Hudson River. Although radio transmissions from the plane could be heard most of the way, transmissions were very intermittent, one of the controllers says, and he is not sure how many minutes of cockpit communications were recorded. Transmissions continued off and on for at least 10 minutes after the turn, he says.
There was another communication to the ground.
A flight attendant is reported to have made a frantic call, saying several passengers had been stabbed.
What flight controllers were saying seems to match the first clues about the identities of the Flight 11 hijackers. Massachusetts authorities have identified five Arab men as suspects and have seized a rental car containing Arab-language flight-training manuals at Logan Airport, according to two Boston newspapers.
Controllers interviewed by the Monitor did not know when the US military was contacted, though doing so is routine after a hijacking is known to be under way. Typically, the Air Force scrambles interceptor jets in the case of hijackings, one controller says.
Two F-15 jets were reportedly dispatched from Otis Air Force Base. Just before or after the military planes got off the ground, however, the controllers report they lost site of Flight 11's radar signal over Manhattan. The controller who had handled the plane from the beginning of the ordeal was stunned.
A few minutes later, the Nashua controllers heard reports that a plane had crashed into a building. They did not know which one.
At 8:45, about 17 minutes after its southward turn toward New York City, Flight 11 - with its 92 passengers and crew - began America's second day of infamy by slamming into the World Trade Center's north tower.
The last minutes of American Airlines Flight 11 have taken a huge emotional toll on the controllers in the Nashua facility. "The guys who handled that flight were traumatized," one says. "You have a special relationship with everyone, every plane you work. They heard what was happening in the cockpit, and then they lost contact."