On June 12, 2016, about 1645 eastern daylight time, American Airlines flight 117, an Airbus A321, N104NN, encountered turbulence in cruise flight at FL170 that resulted in one flight attendant receiving a serious injury. The other 109 passengers and crew members onboard were not injured. The airplane was not damaged. The regularly scheduled domestic passenger flight was operating under the provisions of 14 Code of Federal Regulations Part 121 from John F. Kennedy International Airport (JFK), New York, New York, to Los Angeles International Airport (LAX), Los Angeles, California. The captain stated that after takeoff the he advised the cabin crew to remain in their jumpseats due to possible turbulence. A few minutes later, he announced it was safe to move about the cabin. The captain further stated that seat belt sign was still illuminated at the time of the event, and there were no visible indications of any convective activity in the area. The Captain said that he did not think of this event further, until he was later contacted by a flight attendant who stated that she had been thrown sideways during the turbulence event, and had been injured as a result. The Flight Attendant stated that she did not think much of the incident or injury and she flew for another four days. She then went to her doctor since her ankle was not getting any better and was diagnosed with a fractured foot.