On July 11, 2009, about 1010 eastern daylight time, a passenger aboard N120HQ, an Embraer ERJ-170-20, received a broken ankle when the airplane encountered turbulence while approaching to land at the Indianapolis International Airport (IND), Indianapolis, Indiana. The airplane received no damage. The 14 Code of Federal Regulations, Part 121 flight was being operated by Republic Airlines as flight 3143. The flight was operating in instrument meteorological conditions and was on an instrument flight rules flight plan. None of the other passengers or crew were injured. The flight originated from the Ronald Reagan Washington National Airport, Washington, D.C. at 0835. According to a report filed by the operator, the airplane was on final approach about 15 nautical miles northeast of IND at an altitude of 6,000 feet above mean sea level when the accident occurred. The report stated that the airplane was in continuous light turbulence with occasional moderate turbulence being encountered. The seat belt sign was illuminated. According to a report by one of the cabin attendants, the captain had announced on three separate occasions to remain seated prior to the accident. She stated that the passenger left his seat to use the lavatory and she instructed him to return to his seat and fasten his seat belt. At this time the passenger complied. She stated that about 4 - 5 minutes later, the passenger again left his seat to use the lavatory. She again informed him that it was not safe to be out of his seat and that he needed to return to his seat. The passenger did not comply and entered the lavatory. When returning to his seat, the airplane encountered moderate turbulence and the passenger fell. The captain's report stated that the seat belt sign was illuminated and he had made three separate announcements that turbulence was expected and that passengers needed to remain in their seats with their seat belts fastened for the remainder of the flight. He also commented that he had instructed the flight attendants to remain in their seats when the airplane was about 100 miles from IND.