On June 27, 2007, about 1127 Coordinated Universal time, a flight attendant sustained serious injuries during an in-flight encounter with unexpected turbulence while in cruise flight to Sydney, Australia, on United Airlines flight 863, a Boeing 747-422, N120UA. United Airlines (UAL), Inc., was operating the airplane as a scheduled domestic passenger flight under the provisions of 14 Code of Federal Regulations (CFR) Part 121. The airline transport pilot, first officer, 2 relief first officers, 14 flight attendants, and 264 passengers were not injured; 1 flight attendant received serious injuries. The flight departed San Francisco, California, about 2322 Pacific daylight time, as a non-stop to Sydney. The airplane did not incur any damage. The operator reported that, prior to the encounter, the flight had experienced light chop while in cruise flight at FL330, and the flight crew turned on the seatbelt sign. About 5 minutes later, the flight crew reported that they encountered moderate clear-air turbulence. The captain reported that there were no radar returns within 20 miles, and nothing more than green returns beyond. The flight crew made an announcement over the public address system for the flight attendants to be seated. At the time of the encounter, one flight attendant was entering the top crew rest bunk on the aft wall in preparation for her second rest period. Her balance was not good because she did not have both feet on the ground at the time. When the airplane encountered the turbulence, she fell forward towards the wall. In response, she put her right hand out for protection. Loosing her balance, she fell to the cabin floor. The flight continued to its destination, and upon arrival she was taken to a hospital. As a result of medical information privacy laws, UAL did not learn for several days that she suffered a fracture to her right wrist.