As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, THE -A- SYSTEM HYDRAULIC QUANTITY WENT TO ZERO DURING FLAP RETRACTION. CREW FOLLOWED COM PROCEDURE AND VERIFIED NO FLUID OR PRESSURE IN THE -A- SYSTEM. FLIGHT RETURNED TO MSP AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED BROKEN CLAMP ON MAIN HYDRAULIC SYSTEM FILTER. MAINTENANCE FOLLOWED ALL FLUID LOSS MM PROCEDURES FOR MM 29-11-00, PG 1. ALL LEAK AND OPERATIONAL CHECKS OK.