Pilot error in hazy conditions was ruled the probable cause of the plane crash last summer that killed U.S. Rep. Larkin Smith and his pilot, according to a federal report released Thursday. The National Transportation Safety Board report indicated that pilot Chuck Vierling, who was not rated to fly on instruments, probably lost control after encountering conditions that required them. Vierling, 58, of Gulfport had expressed concern about the haziness before leaving, the report said. Vierling had flown Smith, R-Miss., to Hattiesburg on Aug. 13. On the return flight to Gulfport, the Cessna 152 crashed into woods near New Augusta in southeastern Mississippi. The airplane was about 10 miles off course when it sheared off the top of a pine tree and crashed. Smith, 45, had represented the 5th Congressional District since January 1989.