A forensic anthropologist believes a search for the remains of two French fliers who may have beaten Charles A. Lindbergh across the Atlantic but disappeared in 1927 has turned up a human leg bone, the Maine state medical examiner said. Dr. Marcella Sorg, the state’s forensic anthropologist, examined the bone at the University of Maine at Orono. “She’s pretty confident it’s human,” said Dr. Henry Ryan, the state’s medical examiner. The bone was found by members of The International Group for Historic Aircraft Recovery, or TIGHAR. Searchers have been combing the heavily wooded area north of Machias hoping to find the White Bird, a French biplane that disappeared during a 1927 attempt to fly nonstop from France to New York.