What was found
DURING GEAR RETRACTION, THE CREW HEARD A WHINING NOISE FOLLOWED BY A "POP" AND LANDING GEAR FAILURE CAS MESSAGE. CREW DECIDED TO RETURN TO THE FIELD AND USED THE EMERGENCY BRAKE DURING LANDING; SUBSEQUENTLY THE RT MAIN TIRE BLEW ON LANDING. MX FOUND THE HYD RESERVOIR UNDER-SERVICED AND NO EVIDENCE OF FLUID LEAKAGE ANYWHERE ON THE ACFT. BOTH HYD PUMPS AND THE RESERVOIR WERE CHANGED FOR PRECAUTIONARY MEASURES.