What was found
ON FLIGHT 3709 THE CREW REPORTED THAT APPROXIMATELY 10 MINUTES BEFORE LANDING THEY RECEIVED A HYD 1 LO PRESS EICAS MESSAGE. THE CREW COMPLIED WITH CHECKLIST, DECLARED A PRECAUTIONARY EMERGENCY AND LANDED WITHOUT INCIDENT. THE HYDRAULIC SYSTEM PAGE REVEALED 0% FOR SYSTEM ONE. THE AIRCRAFT WAS REMOVED FROM SERVICE. PERFORMED EDP HYDRAULIC LOSS INSPECTION CHECK IAW CRJ 700 WC 002-05-900-016. REMOVED AND INSTALLED NEW PRESS FILTER IAW CRJ 700 WC 002-05-900-016. REMOVED AND INSTALLED NEW RETURN FILTER IAW CRJ WC 002-05-900-016. REMOVED AND INSTALLED NEW CASE DRAIN FILTERS IAW CRJ WC 002-05-900-016. FILTER ELEMENT, PART NUMBER AC9607F10Y3. ELEMENT FILTER, PART NUMBER 7593394-002. ELEMENT FILTER, PART NUMBER 7593395-001. LEAK CHECK AND OPERATIONAL CHECK GOOD ON ALL. THE AIRCRAFT WAS RETURNED TO SERVICE.