What was found
DURING APPROACH, LANDING GEAR DOOR OPEN LIGHT REMAINED ON AFTER GEAR WAS EXTENDED. GO-AROUND PROCEDURES WERE EXECUTED AND AN UNEVENTFUL LANDING WAS ACCOMPLISHED ON SECOND ATTEMPT. MAINTENANCE FOUND THE LEFT MAIN GEAR DOOR UPLATCH MECHANISM LOOSE. TIGHTENED UPLATCH MECHANISM. ALSO, REPLACED BOTH MAIN GEAR DOOR SKID PLATES DUE TO DAMAGE ON LANDIND. NO SHEETMETAL DAMAGE WAS INCURRED.