What was found
CONDUCTING FLIGHT AV408 FROM SAL TO ORD WHEN A BLUE HYD SYS MALFUNCTION OCCURRED DURING CRUISE PHASE OF FLIGHT. THE CREW REPORTED HYD B RSVR LO LVL & HYD B LO PR DURING FLIGHT, INDICATING A LOW RESERVOIR LEVEL INDICATION AND SUBSEQUENT LOSS OF PRESSURE IN THE BLUE HYDRAULIC SYSTEM. THE APPLICABLE PROCEDURES ACCOMPLISHED, INCLUDING SELECTING THE BLUE HYD ELECTRIC PUMP OFF. CREW DECIDED TO RETURN TO SAL FOR MAINT EVALUATION. NO EMERGENCY DECLARED. ACCORDING TO THE AIRCRAFT TECHNICAL LOGBOOK ENTRY, NO HARD LANDING WAS REPORTED FOLLOWING THE RETURN TO SAL. MAINT PERFORMED TROUBLESHOOTING IAW TSM 29-12-00-810-803-A, REVISION 77, THE BLUE HYD SYS GAUGE TRANSMITTER WAS REMOVED AND REPLACED IAW AMM 29-12-41-000/400-002-A, REVISION 77, HHY LEAKS WERE FOUND DURING THE MAINT INSPECTION. AN OPERATIONAL TEST OF THE FLUID LOW-LEVEL INDICATION SYST WAS SUCCESSFULLY PERFORMED IAW AMM 29-31-00-710-001-A, REVISION 77. BLUE HYD SYS BLEEDING PROCEDURE WAS SUBSEQUENTLY ACCOMPLISHED IAW AMM 29-00-00-870-008/004-A, REVISION 77. AIRCRAFT RETURNED TO SERVICE FOLLOWING SATISFACTORY COMPLETION OF ALL REQUIRED MAINT ACTIONS AND OPS TESTS.