The 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. 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 that night. But the filing suggested that others, including the pilots of the jet and helicopter, also played a role. The lawsuit also blamed American Airlines and its regional partner, PSA Airlines, for 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 flew into the path of the American Airlines regional jet while it was landing at Ronald Reagan National Airport in northern Virginia, just across the river from the nation's capital, officials said. The