A Coeur d'Alene man who had become a popular pilot offering tours of the Grand Canyon died Wednesday when his single-engine plane apparently crashed into the side of a mountain in rugged northwestern Arizona canyon country. Eric Carl Dvoracek, 28, had gone aloft on a routine weather run, officials with King Airelines, a tour company based in Henderson, Nev., near Las Vegas, said Thursday. He appears to have died instantly when his plane struck the side of a mountain and dropped into a canyon, officials with the Mohave County (Ariz.) Sheriff's Office said after reaching the site Thursday.