What was found
(CAN) DURING THE FLIGHT, THE LANDING GEAR TRANSITION LIGHT DID COME ON. EMERGENCY LANDING GEAR EXTENSION C/OUT. LATER AT THE HANGAR, IT WAS FOUND THAT HYDRAULIC FLUID WAS ALL LOST. O-RING AROUND THE SHAFT WAS FOUND CUT ON RT MAIN HYDRAULIC ACTUATOR, PN: ADI-7999-003-3, O-RING AND BACKUP RING REPLACED BY NEW ONE. THIS ACFT IS MODIFIED UNDER STC.