What was found
ENROUTE MASTER WARNING FUSELAGE DOOR CHIMED. DOOR PAGE SHOWED AFT BAG DOOR NOT SECURED. RAN CHECKLIST, MAINTAINED CABIN PRESSURE. REMOVED FROM SERVICE. UPON ACFT ARRIVAL AT THE GATE, FOUND AFT CARGO DOOR HANDLE POPPED OUT. PERFORMED OPERATIONAL TEST OF THE AFT BAGGAGE DOOR IAW Q400 AMM TASK 52-31-00-710-801. DOOR OPERATES NORMALLY WITH NO DEFECTS NOTED. ACFT OK FOR RETURN TO SERVICE. NO PARTS REPLACED.