What was found
SHIP 9586 -ATB/HYD/DE- THE CREW RETURNED THE AIRCRAFT BACK TO MSP AND DECLARED AN EMERGENCY WITH ATC DURING THE APPROACH DUE TO THE LOSS OF THE RIGHT HYDRAULIC SYSTEM FLUID QUANTITY. THE LANDING GEAR WAS EXTENDED USING THE ALTERNATE GEAR EXTENSION PROCEDURES. THE LANDING WAS UNEVENTFUL EXCEPT FOR THE MAIN GEAR DOORS CONTACTING THE RUNWAY. CORRECTIVE ACTION: MAINTENANCE FOUND A B-NUT ON THE TRANSFER LINE TO BE LOOSE AND TIGHTENED IT. ALL OF THE HYDRAULIC PUMPS USED WITHOUT ENOUGH FLUID WERE REPLACED. THE MAIN GEAR DOORS WERE REPAIRED. (LP #5939976)