DCA 15 is closed at night, and other times. By closed in this question I mean: airport management places a gigantic lit/flashing "X" in the landing zone of 15. I'd estimate the big "X" is 8 by 8 feet, at least. It's like one of those roadside trailer flashing signs..except it's a runway.
The flashing X is very evident to pedestrians, bikers etc. on the Mount Vernon trail. It's not some bizarre national secret.
My question: Why... in the tightly controlled airspace of Washington DC... would DCA need to roll out a giant lit "X" to keep planes from landing there?
As if: if the obstruction were not there, you could fly in? ..that doesn't calculate, given how tight the airspace is controlled.
Why does this airport in the center of the world's highest airspace security roll out a construction trailer with a big X to keep planes from landing there?