[...]Someone came in and said, 'Mr. Vice President, there is a plane 50 miles out.' I asked our FAA people, 'Can you see an aircraft coming in 50 miles out?' and they said, 'Yeah, we're tracking it, but the transponder is off, so we don't know what the identification of that airplane is.' Pretty soon the same person came in and informed the vice president, sitting right across from me at the conference table, that the airplane is 30 miles out. I asked the FAA about it and they said, 'Yeah, we know where the plane is, but we don't know who it is.'
Then they came in and said it was 10 miles out. Soon after that, I was talking to the deputy director of the FAA, and he told me they had lost the target off the screen. Soon after that, then, the vice president was informed that there was an explosion at the Pentagon. So I was trying to relate with the air traffic controllers where that plane went to see whether it was close to the Pentagon. The radar is very difficult to pinpoint it to a ground location.[...]
source:
http://www.dailycal.org/sharticle.php?id=8072[...]And a little later on, someone said, "Mr. Vice President, there's a plane 50-miles out." So I was talking to Monte Belger, the Deputy Director of the FAA, and I said, "Monte, what do you have 50-miles out?"
He said, "Well, we have a target, bogey, on the radar, but the transponder's been turned off, so we have no identification of this aircraft. We don't know who it is. We don't know what altitude it's at, speed or anything else. All we're doing is watching with the sweep of the radar, the dot moving from position to position."
So then someone came in, the same person came in and said, "Mr. Vice President, it -- the plane's 30-miles out." So I said, "Monte, can you see it, and where is it in relationship to the ground?"
He said, "Well, that's difficult to really determine. I would guess it's somewhere between Great Falls and National Airport, coming what they call the DRA, the down river approach."
And so then the person came in and said, "Mr. Vice President, the plane's ten-miles out," and so I said, "Monte, where is it?" and he said, "Well, I'm not really sure but I'd be guessing somewhere maybe between the USA Today building and, and National Airport."
And then pretty soon he said, "Oh-oh, we just lost the target." And so a few moments later, someone came in and said, "Mr. Vice President, there's been an explosion at the Pentagon."
So I said, "Monte, is there something -- can you identify it as being at the Pentagon?" He said, "No, we can't really pinpoint it like that."[...]
source: http://www.msnbc.com/modules/91102/interviews/mineta.asp?0cb=-31a105678&cp1=1