What was found
ON FLIGHT FROM KOSU TO KAVL, DURING DESCENT, FELT A SUDDEN VIBRATION FOLLOWED BY THE AIRCRAFT YAWING TO THE LEFT AND A SLIGHT OSCILLATION UP AND DOWN. THERE WAS A RED GEAR UNSAFE LIGHT ILLUMINATED AND A HYDRAULIC PRESSURE CAS MESSAGE WITH THE GEAR HANDLE STILL IN THE UP POSITION. SLOWED THE AIRCRAFT TO A SAFE GEAR DOWN OPERATING SPEED. LOWERED THE GEAR, RECEIVED 3 GREEN DOWN AND LOCKED AND NO RED LIGHT ON GEAR INDICATION. PROCEEDED WITH A NORMAL LANDING AT KAVL WITH NO INCIDENT. TEXTRON AOG TECH FOUND THE L MAIN GEAR UPLOCK HOOK CRACKED IN HALF.