A converted military plane crashed Saturday in heavy fog in the mountains that frame the Salt Lake valley, killing three members of a private firefighting company, authorities said. Sheriff Frank Park said the plane was en route from Montana to New Mexico when it failed to clear a pass in the Oquirrh Mountains. The crew members for Neptune Aviation were bound for southern New Mexico to help fight a nearly 30-square-mile (80-sq. kilometer) wildfire, said Dan Ware, a spokesman for the New Mexico Forestry Division. Search and rescue crews reached the steep, rugged site on foot and all-terrain vehicles to recover the bodies. They were turned over to the state medical examiner, he said. Park said visibility was only 100 feet (30 meters) when the plane failed to clear Stockton Pass. It missed the pass and slammed into a mountain instead, but should have been flying higher, he said.