What happened
On October 12, 2019, an ATR 42-500, registered JA01JC, operated by Japan Air Commuter Co., Ltd., was performing a scheduled flight from Kagoshima Airport to Tanegashima Airport. The flight, carrying 16 passengers and 3 crew members, was in its descent phase at approximately 10,800 feet when the aircraft encountered sudden, localized changes in wind direction and velocity.
As the aircraft's airspeed approached its maximum operating speed (VMO) of 250 kt, the flight crew attempted to manage the speed. The first officer initially set the engine power to flight idle to prevent exceeding the limit; however, the airspeed continued to rise. In an attempt to reduce speed, both the pilot in command and the first officer applied simultaneous, aggressive nose-up control inputs. This maneuver, combined with the increasing speed and existing turbulence, caused the aircraft to experience a significant pitch change and a vertical acceleration of +3.3 G.
During this period of intense shaking, a cabin attendant was walking toward the aft cabin. The sudden movement caused the attendant to lose her balance and fall, resulting in a fractured ankle. Following the encounter, the pilot decided to divert the flight back to Kagoshima Airport. The attendant was transported to a hospital via ambulance for treatment of the injury.