What was found
UPON APPROACH INTO MDT, WHEN GEAR WAS SELECTED DOWN THE NR 2 HYDRAULIC SYSTEM PRESSURE WENT TO ZERO. CREW PERFORMED AN ALTERNATE EXTENSION AND THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT SYSTEM, FOUND THE LANDING GEAR SELECTOR VALVE AT FAULT. REMOVED AND REPLACED THE SELECTOR VALVE IAW DHC PROCEDURES. PERFORMED THE LOSS OF FLUID INSPECTION REQUIREMENTS. OPERATION OF GEAR AND LEAK CHECKED GOOD. A/C RETURNED TO SERVICE. (M)