Although the aircraft regained altitude, 13 passengers and four crew members were injured. The passengers have since been discharged, while the four crew members remain under medical care. Sudden clear air turbulence (CAT) can lift people who have not fastened their seat belts out of their seats and hurl them against overhead panels, armrests or fellow travellers. Nevertheless, the occurrence of clear air turbulence (CAT) is not uncommon. Better forecasts, prompt cockpit warnings and procedures that allow cabin crew members to take their seats earlier can prevent a frightening event from becoming a medical emergency.