Posted on: Sunday, September 16, 2001
The September 11th attack
FBI analyzes data from doomed flights
Associated Press
WASHINGTON — FBI investigators hope to find out what happened in the last minutes of the four commercial airplanes involved in Tuesday's terrorist attack by analyzing the flight data and voice recorders.
The four airplanes were heading to the West Coast when they suddenly switched directions and eventually shut off their transponders, the devices that relay information back to air traffic controllers. But it was nothing that air traffic controllers hadn't seen in the past.
It is not out of the ordinary for a pilot who has problems with a plane to alter course, or even to turn around and head back to the starting point. Even after controllers learned that one of the planes had been taken over, their concern was to make sure the aircraft headed safely to whatever destination the hijackers wanted.
"Controllers are trained to make aircraft in distress your most important aircraft," said John Carr, president of the National Air Traffic Controllers Association. "Pilots are trained to cooperate with hijackers, and controllers are trained to move heaven and earth to help aircraft in distress."
Unlike other hijackings, where a plane eventually lands safely and the crisis is resolved, this time terrorists used the aircraft as a weapon, crashing two planes into the World Trade Center in New York City and a third into the Pentagon. A fourth crashed near Pittsburgh. All of the passengers and crew, including the hijackers, died.
On Friday, search crews found the cockpit voice recorder from the hijacked plane that crashed in western Pennsylvania, an FBI official said, and it was sent to the National Transportation Safety Board in Washington.
That means investigators have recovered four of the "black boxes" — two from American Airlines Flight 77, which slammed into the Pentagon, and two from United Airlines Flight 93, which crashed near Pittsburgh.
FBI Director Robert Mueller said Friday the agency has gotten information from Flight 77's flight data recorder, which tracks an airplane's flight movements, such as altitude, heading, speed and the operations of other airplane systems for the last 25 hours. He declined to say what the FBI has learned.
Mueller said the agency had not gotten any information from the voice data recorder from American Flight 77, which would have recorded all cockpit conversations and communications with air traffic controllers for the last 30 minutes. Mueller did not give information about the recovered flight data recorder from United Flight 93.
Still missing are both recorders from the two planes that destroyed the World Trade Center.
While they automatically record voices and data, the recorders can be disabled by a pilot using circuit breakers in the cockpit. The flight recorders aboard Singapore Airlines' SilkAir Flight MI185 were believed to have been shut off before the Boeing 737 crashed into a river in Indonesia in 1997, killing all 104 passengers and crew members on board.
The recorders also can be damaged in a crash.
Federal officials were notified of the hijacking and the route changes. They were warned when an American plane heading west from Newark Airport turned around and flew in the direction of the White House before making a sharp turn and smashing into the Pentagon.
Asked about the controllers' actions, Carr declined to comment about specific flights. But he said that the controllers followed the procedures outlined in training.
"It has been built into the system that everything is safe," Carr said. "No one contemplated suicidal maniacs using airplanes as weapons. These acts were committed by cowards, despicable barbaric cowards."
