What was found
INSPECTION TYPE:N/AATB - FL340 "CARGO DOOR" EICAS MESSAGE, MASTER CAUTION LIGHT ILLUMINATED, AND AN AURAL WARNING ZONE. COMPLETED QRH CARGO DOOR PROCEDURE (P. 145) DESCENDED TO 10000'. CONSULTED FLT CONTROL AND MAINT-RETURN SDF.MAIN DECK CARGO DOOR INDICATION SYSTEM. FOUND DOOR CLOSED SENSOR S890 AND TARGET GAP .133" WITH DOOR CLOSED, UNLATCHED. ADDED SHIMS TO SENSOR PER AMM 52-71-09-822-037 TO BRING CLEARANCE TO .080. THIS CLEARS M589621.