Controllers Say Flow of Information on Hijacked Planes' Course Was Slow and Uneven

by Matthew L. Wald
The New York Times
September 13, 2001
http://www.nytimes.com/2001/09/13/national/13AVIA.html

 


WASHINGTON, Sept. 12 — The controllers assigned to United Airlines Flight 175 on Tuesday suspected that it had been hijacked as it flew off its assigned route. But they did not learn that another plane had been hijacked and had hit the World Trade Center until a minute or two before Flight 175 struck the center, people involved in the air traffic system said.

In contrast, controllers at the Washington Air Route Traffic Control Center had much more warning that something was wrong. Those controllers, who handled American Airlines Flight 77, which dived into the Pentagon, knew about the hijacking of the first plane to crash, even before it hit the World Trade Center, those involved said. That was more than an hour before they watched another hijacked plane, United Flight 93, cross their radar screen on its way to the Pentagon.

Advance knowledge made no apparent difference in the response; nobody intercepted the plane.

"We issue control instructions," one controller said. "Any procedures beyond that point don't lie with us."

Those procedures would, in fact, lie with the Air Force. The question of giving the Air Force notice of hijackings and authorization to shoot down civilian planes is likely to be a major concern for security officials in the next few days. A spokeswoman for the Federal Aviation Administration said today that there was a policy for when a civilian plane could be shot down, but the agency would not discuss it. The military routinely refuses to disclose its rules of engagement. Nor was it clear today exactly when, or if, the Pentagon was notified on Tuesday.

As the crisis took shape, information flowed unevenly within the F.A.A. The agency has broken up air traffic up into sectors small enough for two controllers to handle, and grouped the sectors in different air traffic offices. Such compartmentalization allows the agency to handle several thousand flights simultaneously, but may also have prevented information from flowing quickly enough.

The F.A.A. has refused to give details, saying that the way the information flows within the agency is part of the F.B.I.'s investigation into Tuesday's attacks. But people involved describe a haphazard flow.

For example, at the New York Air Route Traffic Control Center in Ronkonkoma, which handles long-distance traffic around the New York metropolitan area, the first inkling of a hijacking that most controllers had was when a supervisor came to the cafeteria and asked if he could change the television channel to CNN.

"Our TV's are always tuned to ESPN," one controller said.

The television screen showed one tower of the World Trade Center with a hole in it. "We didn't know what kind, what airplane. There were rumors it was a 737," the controller said. "We said, `No way, it would be a much bigger hole.' We were watching, and we saw the second one go in."

In the darkened, windowless cavern that is the operations floor of the center, most controllers did not learn of the twin hijackings until their colleagues came up from the cafeteria.

At the control tower at La Guardia Airport, the first definitive information for controllers was the sight, viewed through binoculars, of the second plane plunging into the building. On the other hand, as soon as controllers in Boston heard that a plane might have hit the World Trade Center, they knew what had become of American Airlines Flight 11, which they had been tracking since it began behaving erratically, people involved said.

At the New York Terminal Radar Approach Control, the air traffic office whose airspace American Flight 11 entered soon before its crash, a conclusive report of what happened to that plane reached the room only a minute or two before the United plane hit the other tower, controllers there said. "We had 90 to 120 seconds; it wasn't any 18 minutes," said one controller, referring to the actual elapsed time.

Another controller said: "They dove into the airspace. By the time anybody saw anything, it was over."

After the two World Trade Center crashes, controllers at the New York traffic center were briefed by their supervisors to watch for airplanes whose speed indicated that they were jets, but which either were not responding to commands or had disabled a surveillance device called a transponder. Controllers in Washington got a similar briefing, which helped them pick out hijacked planes more quickly. Two of the four planes had transponders that had apparently been tampered with in flight.

In fact, though, transponder failure is an ambiguous sign, even if the plane then strays from its assigned altitude and course. Controllers do not assume the worst "if something weird happens with the airplane," said one; an electrical problem could be responsible and the pilot might be headed back to the departure airport. Standard procedure is to "give him room and watch what he does," another controller said.

Transponders are robot radios, carried in a plane's tail, that respond to queries from ground-based radar by giving the plane's identity and altitude. Ground radar can calculate, based on the timing of the transponder response and the direction from which it came, the plane's latitude and longitude. American Flight 77, which hit the Pentagon, had had its transponder shut off, so controllers had less information on the flight. On United Flight 175, the second plane to hit the World Trade Center, someone changed the code that the transponder was sending, which had the effect of confusing the air traffic control computers. On the controller's screen, the data block, three lines of letters and numbers that give the plane's identity and other details, cut loose from the blip and drifted off.

Controllers also say they were told to watch for planes heading for Camp David, the presidential retreat in Maryland. Unlike the World Trade Center and the Pentagon, Camp David would be hard to spot from the air, but it is clearly marked on charts, because the airspace below 5,000 feet is off limits to civilian planes. But because Camp David is close to Washington and a hijacked plane's target is unknown, it would be hard to say whether a plane headed toward that location actually intended to go there, controllers noted.

 

Copyright 2001 The New York Times Company

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