U.S. Capitol, White House briefly evacuated (CNN)
An apparent airspace violation over Washington on Wednesday prompted evacuations of the White House and the U.S. Capitol as military fighter jets scrambled to intercept an unidentified aircraft.
An all-clear announcement was issued about 15 minutes after the alert.
“Run, this is no joke, leave the grounds,” a U.S. Secret Service agent told CNN White House Correspondent Suzanne Malveaux.
Probably another cloud.
From an update to the above-linked story:
Parts of the White House, Capitol and Supreme Court were briefly evacuated Wednesday when a small plane violated restricted airspace over Washington, the White House said. Fighter jets and a Black Hawk helicopter were scrambled to intercept a high-wing Cessna, said White House spokesman Scott McClellan. President Bush was not at the White House at the time. Vice President Dick Cheney was in the West Wing of the building when the alert was issued and was moved to a secure location, McClellan said.
The plane was within three miles of the White House before it was turned away by the military aircraft, McClellan said.
The terror alert level was raised to orange — or high — when the airspace incursion was first reported, and then raised to red — severe — when the pilot failed to respond to calls on his radio, McClellan said. The plane was escorted to a small airport in Frederick, Maryland. The pilot was being interviewed by local authorities and the Secret Service, McClellan said.
(1502): A map of DC’s air defense system:

Click for much larger image, via Washington Post
map link courtesy Victorino Matus
(1634): ABC’s John Nance asks and answers a question many have had: How Could a Pilot Stumble Into White House Airspace?
How on earth could the pilot of a small aircraft in the year 2005 not realize he or she was about to breach the most sensitive no-fly zone in the nation?
[…]
It seems bizarre, but the truth is that from the air, downtown Washington, the White House, the Capitol building, and all our central governmental buildings seem pretty small.
After the terror attacks of Sept. 11, 2001, Washington’s Reagan National Airport was closed to general aviation and airspace was within a 15¾-mile radius around the Washington Monument was restricted. Since then, hundreds of small aircraft have wandered into the restricted airspace. But how can a pilot tell if he or she has gotten too close? From a low altitude and 15 miles out, even an experienced pilot may not visually see the central D.C. area, even on a clear day. When there is a haze or cloudy conditions, it’s all but impossible for a pilot using vision alone to remain more than 15¾ miles away. Pilots must instead rely on radio navigation, map reading or Global Positioning Satellite equipment. And sometimes, because pilots are human and often make mistakes, even all that isn’t enough.
[…]
And if the pilot of a small plane like a Cessna did intentionally violate the airspace? A Cessna could probably cause very little damage. Unless the plane was loaded with sophisticated high explosives (an Oklahoma City-type bomb would be far too heavy for a light airplane to carry), the amount of kinetic energy we’re talking about is relatively small, and even a direct hit on a major government building would result in very little physical damage to the building.
A small comfort, at least.








