HISTORY OF FLIGHT On February 20, 1996, at 1730 eastern standard time, a Boeing B767-2B7, N656US, operated as a scheduled domestic passenger flight by USAir, Inc., encountered moderate turbulence while in cruise flight at 10,000 feet mean sea level (msl), during the approach for landing at the Pittsburgh International Airport (KPIT), Pittsburgh, Pennsylvania. Of the 139 passengers and 8 crew members on board the airplane, six flight attendants and one passenger received minor injuries. The airplane was not damaged. The flight was operating on an IFR flight plan at the time of the turbulence encounter. The flight operated under 14 CFR Part 121, and originated from Boston, Massachusetts, at about 1605. The captain stated that the airplane was in level flight at 10,000 feet msl, in a thin cloud layer about 30 miles northeast of the destination airport, operating at an indicated airspeed of 290 knots, when the flight encountered approximately six seconds of moderate turbulence. He said the seatbelt sign was illuminated, and the routine arrival public address (PA) announcement had been performed. He said that before and after the unforecast turbulence encounter, the flight had been smooth, and all operations were normal. The six flight attendants were performing arrival duties when the turbulence encounter occurred, and they received minor injuries. One passenger, who was in the aft lavatory, also received minor injuries. Upon arrival at Pittsburgh, paramedics met the flight and the injured persons were taken to the Ohio Valley Hospital, treated, and released. (Flight attendant statements are appended.) The flight attendants stated that they were all standing in various areas of the aircraft preparing for landing when the turbulence encounter occurred. They said that, although the seatbelt sign was on, one passenger had disregarded the sign and had gone to the aft lavatory. The flight attendants reported that the first jolt of turbulence got their attention, then moments later they were in the air. They indicated that they bumped their heads on the ceiling/overhead bins, then landed on the floor. The flight attendants indicated that, after they recovered, they made inquired to see if any of the passengers were injured. The flight attendants then secured themselves in their jumpseats until the airplane had safely landed. ADDITIONAL INFORMATION One flight attendant was initially diagnosed with a serious "Nondisplaced T6 vertebral body fracture," however, subsequent reviews of the X-rays by medical experts revealed that the T6 fracture could not be confirmed. (Medical evaluations are appended.)