What was found
DURING FLIGHT, PILOT NOTED THE ACFT SEEMED SLOWER AND YAWING TO THE LEFT. FLYBY INDICATED THE LEFT MAIN LANDING GEAR WAS DOWN WHILE THE RT AND NOSE WERE RETRACTED GEAR. SELECTED DOWN, ALL THREE INDICATED DOWN AND LOCKED. ACFT LANDED AT MAINTENANCE BASE WITHOUT INCIDENT. INVESTIGATION REVEALED THE LEFT MAIN GEAR TORQUE TUBE HAD CRACKED AT THE FORK BOLT BOSS AND THE CRACK HAD PROGRESSED AROUND THE TORQUE TUBE IN A SPIRAL MANNER.