The midair collision Wednesday night between a regional American Airlines passenger jet and a Black Hawk military helicopter over the Potomac River near Washington, D.C., was "absolutely" preventable,

"The Army pilot made a grave error," Timothy Lilley said. "It hurts me because those are my brothers, and now my son is dead."

The search and rescue mission was transitioning to a recovery mission, and no survivors were expected, DC Fire and EMS Chief John Donnelly said.