What was found
DURING ENGINE START, PRIOR TO THE DEPARTURE OF THE AIRCRAFT FLIGHT AV503, PILOT REPORTED LOW PRESSURE ON BLUE HYDRAULIC SYSTEM; CONSEQUENTLY, THE AIRCRAFT WAS RETURNED TO BLOCK. AT MAINTENANCE, AND PER TSM 29-12-00-860-053-C, THE BLUE HYD. SYSTEM WAS FOUND OVERFILLED. BLUE HYD. SYSTEM WAS PROPERLY SERVICED PER AMM AND CORRECTED REPORTED FAILURE. THE AIRCRAFT WAS RETURNED TO SERVICE.