On February 8, 1999, at 1841 eastern standard time, a McDonnell Douglas, MD-80, N433AA, encountered severe turbulence, 10 miles southwest of the South Boston VOR during let down into Raleigh, North Carolina. Flight 1754, a scheduled domestic passenger flight, was operated by American Airlines under the provisions of Title 14 CFR Part 121 with an instrument flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane was not damaged; the pilot, the first officer, and 131 passengers were not injured. Three flight attendants received minor injuries, and one flight attendant was seriously injured. The flight departed Chicago, Illinois, at 1718. According to the pilot, the airplane was descending through 17,000 feet for an approach into Raleigh, North Carolina when severe turbulence was encountered. The flight attendants were securing the passenger cabin and galley for landing at the time of the occurrence. The pilot reported that the fasten seat belt sign was on. According to the flight crew, clear air turbulence was not forecasted. The examination of the Digital Flight Data Recorder (DFDR), a Sundstrand model UFDR, showed that the turbulence was encountered at an altitude of approximately 17,462 feet on a magnetic heading of approximately 144 degrees. The DFDR also revealed that during the turbulence, vertical acceleration reached a maximum of 2.05 G's and a minimum of -.49 G's. Lateral acceleration reached a maximum of .21 G's and a minimum of -.11 G's. Longitudinal acceleration reached a maximum of .1 G's and a minimum of -.02 G's. According to the data, the autopilot was turned off approximately six seconds after the turbulence began. The autopilot was turned on about seven seconds after it was turned off (see attached Flight Data Recorder Readout Report). The seriously injured flight attendant sustained an L-1 compression fracture.