On August 16, 2010, at about 10:05 PM eastern daylight time, British Airways flight 265, a Boeing 767-300ER, registration G-BNWU, experienced turbulence while on approach to Washington Dulles International Airport (IAD), Dulles, Virginia. One flight attendant received serious injury when she fell in the aft galley. There were no injuries to the other 185 passengers and eight crew members and the airplane was not damaged. The regularly scheduled passenger flight was operating under the provisions of 14 Code of Federal Regulations Part 129 from London-Heathrow International Airport (LHR), London, United Kingdom. Night visual meteorological conditions prevailed at the time of the accident. The first officer was the flying pilot. The takeoff, climb, cruise and initial decent phases of the flight were normal and uneventful. According to the flight crewmembers’ statements, the descent briefing was completed early due to an anticipated early descent in U.S. airspace. During the initial descent into IAD, the flight crew requested vectors from air traffic control (ATC) to avoid a small cumulus (Cu) buildup along the cleared route. At this time, about 20 minutes before landing, the crew made a public address announcement and turned on the seatbelt sign. The first officer indicated that the flight remained in smooth conditions and avoided the Cu by about 5 miles. The flight crew stated that as the flight was being vectored to the localizer for runway 16C, the airplane entered the thin cloud tops in a descending left turn and felt a brief “jolt” of turbulence. According to the quick access recorder (QAR) data, as the airplane was descending through about 8,100 feet pressure altitude, the normal acceleration increased suddenly to 1.69 g as the airplane was in a 25 degree left bank. According to the injured flight attendant (FA), she was securing the aft galley for landing when it started “to get bumpy and the purser said, “let’s sit down.” As she was heading toward her jump seat, the jolt of turbulence caused her to be thrown into the air and land on the floor face first. At the time of the event, the Slide Arm Indicator was set to white (which indicates to the flight crew that the cabin is secure) even though the flight attendants were still securing the cabin for landing. Shortly after the airplane was established on final approach, the flight crew overheard that a FA had sustained injuries as they monitored the cabin interphone. After a brief conversation with the senior FA, the flight crew decided to continue the approach and manage the problem on the ground. The flight crew indicated that they did not alert ATC at this time because they were unaware of how serious the injuries were. After landing, the cabin service director (CSD) advised the crew that medical assistance would be required. They were unable to contact the company during the taxi and so advised the ground crew that a paramedic was required immediately after parking at the gate. The flight crew estimated that the paramedics arrived about 5 minutes later. FLIGHT ATTENDANT STATEMENTS The CSD stated that, at the time of the turbulence, the airplane was on final approach about 5-6 minutes from landing with the seatbelt signs on. The CSD further indicated that there was no advanced warning of the turbulence. The injured flight attendant was treated with a cold compress and ice pack until she was transported to the hospital. INJURIES According to the injured FA, she was hospitalized for two days and was diagnosed with fractures to her right and left cheekbones, a crushed nerve, whiplash, and bleeding into muscles in the neck. METEOROLOGY IAD Terminal Forecasts From August 16, 2010, 2100 UTC (1700 EDT); winds variable at 3 knots, visibility greater than 6 statute miles, showers in the vicinity, and clouds broken at 3,500 feet and overcast at 5,000 feet. From August 17, 2010, 0300 UTC (2300 EDT); winds from 320 degrees at 4 knots, visibility greater than 6 statute miles, and clouds broken at 5,000 feet and overcast at 7,000 feet. IAD METAR August 17, 2010, 0152 UTC (2152 EDT); winds from 200 degrees at 3 knots, visibility greater than 10 statute miles, a few clouds at 10,000 feet, temperature 26 degrees C, dew point 23 degrees C, and altimeter 29.96.