I saw an animation of the ATC plot for the aircraft last night on TV. XPDRS were reportedly turned off.
This story has just been published;
Pilot sent secret messages - report
BOSTON (Reuters) - The pilot of American Airlines Flight 11, which crashed into New York's World Trade Centre on Tuesday, secretly sent messages to controllers on the ground during much of the flight, the Christian Science Monitor has reported.
The paper, citing interviews with two unnamed air traffic controllers, said the pilot was apparently triggering a "push to talk" switch in the cockpit, probably on the plane's steering wheel, known as a yoke.
"The button was being pushed intermittently most of the way to New York," one of the controllers told the newspaper's Thursday edition. "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 threatening the pilot and it was clearly threatening."
During the transmissions, the pilot's voice and the heavily accented voice of a hijacker were clearly audible, the controllers told the paper.
The transmissions were all recorded and the paper said the tapes were turned over to federal law enforcement officials.
The paper said controllers were first tipped off that something was wrong on Flight 11 when the aircraft failed to follow an instruction to climb to its cruising altitude of 31,000 feet (9,449 metres).
"He was cleared to continue his climb and he did not," the paper quoted one of the controllers as saying. "He was given permission to turn to go around (other airplane) traffic at 29,000 (feet/8,839 metres). So he issued a further climb, and (the plane) does not respond. That was the first indication we had of a problem," the controller told the newspaper.
The controller handling the plane then tried repeatedly to raise the aircraft on the radio but got no response. He then switched to an emergency frequency but again failed to establish contact.
At about the same time, some 20 minutes into American Airlines Flight 11's trip, the aircraft's transponder stopped working, making its altitude a matter of guesswork. Without the transponder, the plane was still visible on radar.
"Then the plane turned (south toward New York), and then they heard the transmission with the terrorist in the background," the controller told the paper.
"The voice upset him 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," the controller said.
The controllers also said that they heard a hijacker say something like "We have more planes, we have other planes," although the statement's import was not understood.
Another controller in the Federal Aviation Administration Control Center in Nashua, New Hampshire, confirmed the events to the newspaper.
"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,'" the second controller told the paper.