What was found
(CAN) ON APPROACH CREW REPORTED COMPLETE LOSS OF HYD FLUID FROM 'A' SYS UPON SELECTION OF FLAPS & MLG. CREW CONDUCTED MISSED APPROACH & PROCEEDED TO COMPLETE 'LOSS OF SYS HYDRAULICS NON NORMAL CHECKLIST. CREW PERFORMED VISUAL APPROACH & LANDED A/C WITHOUT INCIDENT. MAINT INSPECTION REVEALED NR 1 OUTBOARD GROUND SPOILER ACTUATOR CASE HAD SPLIT RESULTING IN COMPLETE LOSS OF HYDRAULICS. MAINT ENGINEERS CHANGED ACTUATOR, AND ENGINE DRIVEN HYDRAULIC PUMPS & CHANGED / CHECKED ALL RELATED FILTERS FOR CONTAMINATION. SYS GROUND CHECKED SERVICEABLE & A/C RETURNED TO SERVICE WITH NO FURTHER INCIDENTS TO REPORT.