What was found
FWD CARGO DOOR OPEN INDICATED AROUND 45KTS ON T/O ROLL. ANOTHER ACFT CONFIRMED OPEN. FOUND FWD CARGO DOOR OPEN WITH DOOR HANDLE STOWED IN THE LOCKED POSITION. INSPECTED DOOR FRAME CAM RECEIVERS FOR FOD. NONE FOUND. DOOR STOPS ARE CLEAR. FWD CARGO DOOR HANDLE HAS TENSION. OPENED AND CLOSED DOOR SEVERAL TIMES. DOOR STAYS CLOSED. DOOR ONLY COMES OPEN WITH TAKEOFF ROLL WITH HEAVY VIBRATION . REMOVED INTERIOR HANDLE ACCESS PANEL, FOUND ACTUATOR SPRING BROKEN , PERFORMED VISUAL INSP OF DOOR MECHANISM AND FOUND NO DAMAGE OTHER THAN BROKEN ACTUATOR SPRING. REPLACED ACTUATOR SPRING IAW AMM 52-31-74-400-801, DOOR OPS CHECKED GOOD. DOOR OPENS AND CLOSES NORMAL