WASHINGTON, Sept. 14 — During the hour or so that American Airlines Flight 77 was under the control of hijackers, up to the moment it struck the west side of the Pentagon, military officials in a command center on the east side of the building were urgently talking to law enforcement and air traffic control officials about what to do.
But despite elaborate plans that link civilian and military efforts to control the nation's airspace in defense of the country, and despite two other jetliners' having already hit the World Trade Center in New York, the fighter planes that scrambled into protective orbits around Washington did not arrive until 15 minutes after Flight 77 hit the Pentagon. Even if they had been there sooner, it is not clear what they would have done to thwart the attack.
The Federal Aviation Administration has officially refused to discuss its procedures or the sequence of events on Tuesday morning, saying these are part of the Federal Bureau of Investigation's inquiry. But controllers in New England knew about 8:20 a.m. that American Airlines Flight 11, bound from Boston to Los Angeles, had probably been hijacked. When the first news report was made at 8:48 a.m. that a plane might have hit the World Trade Center, they knew it was Flight 11. And within a few minutes more, controllers would have known that both United 175 (the second plane to hit the World Trade Center) and American 77 (which hit the Pentagon) had probably been hijacked.
Flight 77, which took off from Dulles International Airport outside Washington shortly after 8 a.m., stayed aloft until 9:45 a.m. and would have been visible on the F.A.A.'s radar system as it reversed course in the Midwest an hour later to fly back to Washington. The radars would have observed it even though its tracking beacon had been turned off.
By 9:25 a.m. the F.A.A., in consultation with the Pentagon, had taken the radical step of banning all takeoffs around the country, but fighters still had not been dispatched. At that same time, the government learned from Barbara Olson, a political commentator who was a passenger on Flight 77, that the plane had been hijacked. She twice called her husband, Solicitor General Theodore B. Olson, on her cellular phone to tell him what was happening.
Despite provisions for close communication between civilian and military traffic officials, and extensive procedures for security control over air traffic during attacks on the United States, it does not appear that anyone had contemplated the kind of emergency that was unfolding.
The procedures, first devised in the 1950's, cover how to send fighter planes to shadow a hijacked plane on its way, perhaps, to Cuba. They tell how to intercept a plane entering the nation's airspace through the air defense zone along the Atlantic Coast, but not what to do with kamikazes.
"There is no category of `enemy airliners,' " a recently retired F.A.A. official said. He and others said they *could not recall any instance in which a military plane fired on a civilian one in the United States, though in 1983 a F-4 Phantom fighter that scrambled to intercept an unidentified target off Cherry Point, N.C., accidentally rammed it. That plane was a private twin-engine propeller plane on the way home from the Bahamas, carrying seven people.
The United States is signatory to a treaty that appears to bar using force against civilian airplanes. Congress has voted against letting the military shoot down suspected drug planes trying to cross into the United States. Whether those restrictions would apply to a plane showing clearly hostile intent has never been spelled out. An F.A.A. spokeswoman said earlier this week that there was a policy for shooting down civilian airliners but would not divulge it.
And shooting down a jet as large as a Boeing
John S. Carr, president of the National Air Traffic Controllers Association, the controllers' union, said: "Our system of unfettered access and freedom has limitations in terms of responding to a case like this. We've created a system for transportation, not defense."
Today officials were trying to reconstruct that system. Ronald Reagan National Airport — with approaches that are within a few hundred yards of the Pentagon and just seconds, at jet speeds, from the heart of Washington — remains closed, "temporarily and indefinitely." Private planes were allowed to resume flying at 4 p.m. today, but only under air traffic control.
Combat aircraft are patrolling the skies; an aircraft carrier is at sea off Washington and another off New York to provide air defense.
Military officials have offered vague descriptions in public about their procedures against airborne terrorists. In a confirmation hearing on Wednesday before the Senate Armed Services Committee, Gen. Richard B. Myer of the Air Force, who has been nominated to be chairman of the Joint Chiefs of Staff, said he did not know whether the F.A.A. had contacted the Pentagon about the hijackings.
"When it became clear what the threat was, we did scramble fighter aircraft, AWACS, radar aircraft and tanker aircraft to begin to establish orbits in case other aircraft showed up in the F.A.A. system that were hijacked," he said. He added that once the fighters were aloft, it was not necessary to use force.
In part, that was because American Airlines Flight 77 had already hit the Pentagon, and the hijacked flight from Newark, its target unknown, had crashed in Pennsylvania.
Paul Wolfowitz, the deputy defense secretary, said today that the Pentagon had been tracking that plane and could have shot it down if necessary; it crashed about 35 minutes after the Pentagon crash.