What happened
The aircraft was operating at a cruise altitude of 37,000 feet within cirrus cloud cover. During this phase of flight, the airplane encountered moderate to severe turbulence. At the time of the event, the autopilot was engaged and the seat belt warning signs were turned off.
The flight crew responded to the turbulence with abrupt control inputs to maintain aircraft control. These actions were necessary to manage the aircraft's attitude during the turbulent encounter.
Findings
Post-flight inspection revealed that there was no damage reported to the airplane structure or systems. However, the physical forces involved resulted in injuries to occupants. A total of 17 persons on board reported minor injuries. The lack of seat belt signs being illuminated likely contributed to the injury count as passengers may not have been securely fastened during the encounter.