What was found
IAH- DURING FLIGHT 3600 THE CREW NOTED THAT NOSE LANDING GEAR ON #1 SYSTEM SWITCHED FROM LOCKED TO UNLOCKED IN FLIGHT, ON GROUND WAS DOING SAME THING, BUT WITH LOUD BANGING, AND, #2 HYDRAULIC SYSTEM LOOSING 1,000 PSI. IAH- MAINTENANCE REMOVED AND REPLACED THE RIGHT HAND NLG PROXIMITY SWITCH REF. ATR 42 JIC 32-61-00, AND, THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.