On August 30, 2001, at 1555 eastern daylight time, an Embraer ERJ-135ER, N25504, operating as Continental Express flight 3608, was undamaged during a turbulence encounter near Richmond, Virginia. The captain, first officer, and 26 passengers were not injured. One flight attendant was seriously injured. Instrument meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the flight that originated at Cleveland-Hopkins International Airport (CLE), Cleveland, Ohio. The scheduled passenger flight was destined for Richmond International Airport (RIC), Richmond, Virginia, and conducted under 14 CFR Part 121. According to the airline's senior manager of flight safety, the airplane was on autopilot, descending through 17,000 feet, at 280 knots. It was being operated in an area of convective activity, with cells about 20 nautical miles on either side of the flight path. There were no radar echoes in the path of flight. The captain notified the flight attendant that the "ride may be bumpy," and had her sit down. The seat belt sign was illuminated, and a general announcement about potential turbulence was made. Approximately 10 minutes after the announcement, severe turbulence was encountered. The flight attendant, who had been standing near row 12 at the time, was then seriously injured. The senior manager of flight safety for Continental Express interviewed the pilots and the flight attendant by telephone, and prepared summaries of each interview. All three crewmembers gave a similar accounting of events. The first officer said that when the severe turbulence was encountered, it caused his hands and feet to come off the controls. He also said that the autopilot disconnected and the airplane banked about 15 degrees. According to the flight attendant, the captain called and advised her that he expected to encounter turbulence within 5 to 10 minutes, and that she was to secure the galley and sit down. She closed the galley and took her seat. A few minutes later, she felt the airplane bounce a few times. "I thought we were through the turbulence and got up to complete cabin preparations for landing. As I got to the back of the aircraft, we hit severe turbulence that knocked me to the floor. It felt like we went down-up-down. My leg and ankle folded under me and I immediately knew that I had broken my leg." When the flight attendant was asked why she got out of her seat before the captain advised her, she said: "After we encountered the [first] bumps, it got smooth. Normally the crews do not advise us when we are over the turbulence." All three crewmembers were asked if there was any specific guidance in the company's flight operations manual about seating cabin crewmembers in anticipation of turbulence. None of the three was aware of any. When the captain was asked if he told the flight attendant how long to stay seated, he stated: "Not that I recall. I thought she would stay seated until I told her otherwise." A review of information from the flight data recorder (FDR) revealed that the airplane encountered an area of turbulence, about 1547. The turbulence lasted approximately 3 minutes and varied in magnitude from a positive 1.25g to a negative .25g. The airplane resumed relatively smooth flight for about 4 minutes. At that point, there was a vertical acceleration to over 3g's. There was also roll divergence of about 20 degrees both left and right. As a result of the investigation, and after coordination with the senior manager of flight safety for Continental Express, the airline published a Cabin Information Letter for cabin crews, and a Flight Information Letter for flight crews with the following guidance regarding turbulence: Flight Crew: · Ensure the Seatbelt sign is ON · Slow the aircraft to turbulence penetration speed · If required, Notify the FA to be seated and remain seated until further advised by the PIC · Make a PA (public address) as appropriate · Advise the FA when normal duties may be resumed Flight Attendants: · Remain seated until further advised by the PIC · Make a PA as appropriate to passengers (if Flight crew has not) · Resume normal duties when advised by the PIC only