The National Transportation Safety Board released a simulation of last year’s mid-air collision near Ronald Reagan National Airport in Washington, D.C. that killed 67 people. The cockpit-view reconstruction shows the military helicopter was barely visible until seconds before impact due to night lighting and blind spots. Investigators said warnings came too late, leaving pilots with no time to avoid the collision. The crash, involving an American Airlines passenger jet and a Sikorsky UH-60 Black Hawk, was the deadliest aviation accident in the US since 2001.