A United Airlines Boeing 747-400, registration N173UA performing flight UA-897 from Washington Dulles,DC (USA) to Tokyo Narita (Japan) with 227 passengers and 18 crew, was enroute overhead Alaska about 70nm east of Anchorage descending from FL320 to FL300, when the airplane encountered turbulence causing injuries to 18 people on board. The airplane continued to Tokyo's Narita Airport, where the airplane landed safely about 7 hours later. Japanese Police reported, that one passenger received serious injuries (fractured leg), 17 occupants received minor injuries. Japan's Transport Ministry reported, that the airplane was descending from FL320 to FL300, when it encountered the turbulence...