|Staff members and workers at the US Capitol, line up as they return to the building following an evacuation|
It was just before noon on a clear spring day that the small single-engine Cesna aircraft crossed an imaginary line in the sky about 100 kilometers north of downtown Washington. The plane triggered an alarm through the radar system of the civilian Federal Aviation Administration. Air traffic controllers tried to contact the aircraft, but it did not respond to radio calls and was not sending the required electronic signal that would indicate it had authorization to enter Washington's restricted airspace.
Officials initiated an alert that was received moments later at the North American Air Defense Command (NORAD) some 2,600 kilometers to the west in Colorado. A NORAD spokesman, U.S. Navy Lieutenant Commander Sean Kelly, explains what happened next.
"As soon as the FAA designated the aircraft as a 'flight of interest,' when they started tracking this specific plane as a potential problem, they activate what is called the Domestic Events Network, which brings NORAD, Homeland Security, and a bunch of other organizations up on line to say, 'we've got something we need to track,'" said Mr. Kelly.
As the situation developed, among those receiving a warning that a suspect aircraft had entered Washington's restricted airspace was the Secret Service, the government force responsible for protecting the president and other senior officials. President Bush was outside the city, on a recreational outing in the suburbs. But White House spokesman Scott McClellan says officers at the White House swung into action anyway.
"At approximately 12:01 the threat level was raised to orange,” said Mr. McClellan. “The plane was within 10 miles and an evacuation and moving of people to more secure locations began at that point. And then, at 12:03 the alert level was raised to red. The Cesna was within three miles of the White House before it turned west and started traveling away from the White House.”
Three miles is a little less than five kilometers. Security officers ordered officials, visitors, journalists and everyone else in the White House, the Capitol building and the Supreme Court to run away from the buildings as fast as they could, and they did.
Mr. McClellan says Vice-president Dick Cheney left the building by car, and President Bush's wife Laura, and former first lady Nancy Reagan, who was visiting, were moved to a secure location.
Meanwhile, the North American Air Defense Command ordered two F-16 fighter jets launched from Andrews Air Force Base near Washington. The aircraft intercepted the small plane, and witnesses say they flew circles around it and fired flares to get the pilot's attention. A helicopter from the U.S. customs service also headed to the area.
Lieutenant Commander Kelly says the pilot and his passenger were in considerable danger.
"Whenever a fighter plane goes up like that on this type of mission, there is always the chance that somebody will get shot down. You don't send up a fighter plan to just look mean. NORAD has the authorization to use lethal force, if necessary. How close did this get to it? I cannot say for certain. Obviously the pilot did respond to the F-16s and turned away," he explained.
With the plane just about five kilometers from the White House there was only a little more than a minute before it might hit the building. The pilot turned away just in time.
About eight minutes after the White House security alert level went to red, it was moved back down to its normal level. A few minutes later officials issued an all-clear announcement. The whole incident had lasted just about half an hour.
But, as dramatic as Wednesday's emergency was, Lieutenant Commander Kelly of NORAD says violations of restricted airspace around Washington and elsewhere in the country are not really unusual.
"The fact that we had to send planes to intercept, not that unusual. I believe right now it's more than 1,800 times since September 11, we've had to divert or scramble airplanes to intercept somebody violating a flight restriction such as exists around the DC area," he added.
But usually the aircraft turn away long before they get as close to the White House and the Capitol building as this aircraft did.
Officials are praising the various security agencies for their coordinated response to this alert, and for the fact that they did not order the fighter pilots to shoot down a plane that turned out, apparently, not to be involved in any kind of attack.
But at the same time questions are being raised about the response, whether enough people were warned quickly enough, and even whether there may have been some over-reaction, resulting in videotape broadcast around the world of people fleeing the White House and the Capitol when they didn't really need to. In the coming days and weeks, officials will be evaluating the incident and, as they always do in such situations, seeking what the military calls 'lessons learned.'