Airspace is complicated. Experts say Trump's arch would add one more risk

The Trump administration is moving ahead with a proposed 250-foot arch at Memorial Circle, a traffic island on the historic bridge linking Washington, D.C., to Arlington, Va. The location sits about two aeronautical miles from Ronald Reagan Washington National Airport’s main runway, one of the busiest in the U.S., where aircraft pass every 45 to 60 seconds for much of the day. A June FAA preliminary report said the arch would likely be acceptable if equipped with blinking red obstruction lights, but the agency is still running a broader review that could label it a hazard. Aviation experts NPR spoke with say the arch adds risk variables in a highly congested airspace.