What happened
Before descending from cruise altitude, the cockpit crew notified the second and third flight attendants via intercom that turbulence was expected during the descent for landing. The crew instructed the attendants to secure the cabin and take their seats.
Following this instruction, the first attendant focused on securing the first-class section, while the second flight attendant moved from the front of the aircraft toward the rear. While performing duties such as collecting service items and checking passenger seat belts, the second attendant reached the rear of the cabin. At that time, the aircraft encountered turbulence, prompting both the second and third flight attendants—who was working in the aft galley—to take their seats and fasten their seat belts.
After approximately one to two minutes of moderate turbulence, the motion subsided, and the two attendants stood up to resume work in the aft galley. A subsequent bout of additional turbulence occurred, causing the second flight attendant to fall to the galley floor. The third flight attendant also fell, landing on the foot of the second attendant, which resulted in a broken ankle for the second attendant.
The investigation
Analysis of the flight data recorder revealed that during the descent, vertical acceleration values fluctuated between 0.65 g's and 2.02 g's within a single one-second period.