What happened
During a cruise phase of flight, the captain departed the cockpit to conduct an inspection of the cargo hold. While he was occupied with this task within the cabin, the aircraft encountered turbulence that had not been forecasted by meteorological services. The sudden movement caused the captain to fall, resulting in a broken ankle. Following the incident, the first officer assumed control and returned the airplane to the departure airport for further evaluation.
The investigation
The operator reported that the airplane sustained no structural damage during the event. The primary focus of the immediate aftermath was the medical condition of the crew member rather than mechanical failure or airframe integrity.