The U.S. government admitted Wednesday that the Federal Aviation Administration and the Army played a role in causing the collision last January between an airliner and a Black Hawk helicopter near the nation's capital, killing 67 people in the deadliest crash on American soil in more than two decades. The official response to the first lawsuit filed by one of the victims’ families said that the government is liable in the crash partly because the air traffic controller violated procedures about when to rely on pilots to maintain visual separation that night. Plus, the filing said, the Army helicopter pilots' “failure to maintain vigilance so as to see and avoid” the airline jet makes the government liable. But the filing suggested that others, including the pilots of the jet and the airlines, may also have played a role. The lawsuit also blamed American Airlines and its regional partner, PSA Airlines, for roles in the crash, but those airlines have filed motions to dismiss. At least 28 bodies were pulled from the icy waters of the Potomac River after the helicopter apparently fle