What was found
FWD CARGO DOOR UNLOCK WARNING AND ECAM MESSAGE AT 18,000' AND PSID 7.0, SPEED 340 KTS. PREECEDING THE CARGO DOOR UNLOCK WARNING BY LESS THAN 1" WAS A LOUD "THINK" FROM UNDERSIDE OF AIRCRAFT. SLOWED TO 240 KTS, NO CHANGE. DEPRESSURIZED AND DESCENDED AND PSID 4.0 THE WARNING DISAPPEARED. ADJUSTED FWD CARGO DOOR SWITCH 14WS IAW FEDEX A310-200 AMM 52-71-11, AND ACCOMPLISHED AN INSPECTION OF FWD CARGO DOOR SILL AND FRAME AREA. NO DISCREPANCIES NOTED IAW FEDEX A310-200 AMM 52-31-11.