What was found
PILOT REPORTED THE LEFT PROPELLER CONTROL WAS UNRESPONSIVE AT CLIMB OUT AND PERFORMED AN AIR RETURN. COMPANY MAINTENANCE INSPECTED THE LEFT PROPELLER AND FOUND CRACKS IN THE PROPELLER HUB AT ALL 3 BLADE SOCKET LOCATIONS. AT BLADE 1 LOCATION THE CRACK IS APPROXIMATELY 75% OF CIRCUMFERENCE. AT BLADE 2 LOCATION CRACK IS APPROXIMATELY 50% OF CIRCUMFERENCE. AT BLADE 3 LOCATION CRACK IS JUST VISIBLE AND LESS THAT 1 INCH. THE PROPELLER HAS BEEN REMOVED FOR TEAR DOWN EVALUATION BY MCCAULEY SERVICE CENTER. OPERATOR HAS INSTITUTED A FLEET WIDE DETAILED VISUAL INSPECTION.