What was found
AIRCRAFT WAS GROUNDED: PILOT REPROTS DURING DESCENT, PASSING 18,000 TURNED ON BOTH HYDRAULIC PUMPS TO HIGH. RIGHT HYDRAULIC PRESSURE DROPPED TO ZERO & RIGHT HYDRAULIC LOW PRESSURE LOW LIGHT CAME ON. TRANSFER CONT/AUX PUMPS WERE NOT ON. THIS LASTED ABOUT 2 MINUTES. TURNED BOTH HYDRAULIC PUMPS TO LOW & PRESSURE RETURNED TO NORMAL PRESSURE THERE AFTER. MAINTENANCE REPLACED RT ENGINE DRIVEN HYDRAULIC PUMP AND CASE DRAIN FILTER ELEMENT IAW AMM 29-10-05 AND AMM 29-10-14. OPS CHECK OK. NO LEAKS NOTED.