The President's Plane Is Missing (1973)

While on the brink of a military confrontation with China, Air Force One crashes in the desert, killing the President. This brings Vice-President Kermit Madigan to power who, having been left in the dark by the president, must now rely on his predecessor's aides to guide him. But they have markedly different viewpoints and hidden agendas. Will he blunder his way into a nuclear exchange with the Chinese?