ACR B727 FLOWN BY MORE THAN 1 FLC IN NON COMPLIANCE WITH MEL. REF MULTIPLE FUEL SYS PROBS.

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THE ACFT ASSIGNED ARRIVED AT GATE FROM OUT STATION WITH 2 MAINT CARRYOVERS UNDER 2 SEPARATE MEL ITEMS: #1 TANK FUEL QTY INOP AND FUEL DUMP 2R VALVE INOP. ON FLT PLAN; BOTH ITEMS APPEARED INDICATING MAINT AND FLT CTL DISPATCH APPROVAL. ACFT LOGBOOK REFLECTED BOTH ITEMS AND AN AIRWORTHINESS RELEASE. I HAVE BEEN A CAPT ON THE B727 FOR 8 MONTHS; BUT FROM PREVIOUS EXPERIENCE; I REMEMBERED THAT FUEL DUMP REQUIRED WORKING FUEL GAUGES AND VICE VERSA. I ASKED OUR FE TO MAKE SURE THESE 2 ITEMS DID NOT CONFLICT. I OBSERVED THE ENGINEER READING THE MEL. AT THAT TIME; AND LATER DURING PRE-DEP BRIEF HE CONFIRMED THE 2 ITEMS DID NOT CONFLICT. UPON ARR AT DEST; THE NEXT CREW DETERMINED THAT THE ACFT COULD NOT BE AIRWORTHY WITH THESE MAINT CARRY-OVERS. FACTORS: MEL FOR FUEL DUMP; DOES NOT REF FUEL QTY GAUGES; ONLY FUEL QTY ITEM REF FUEL DUMP. FLT CTL; MAINT CTL AND PREVIOUS CREW ACCEPTED ACFT AS AIRWORTHY. ACFT 'FLEW IN' WITH THESE ITEMS. IT WAS EASY TO BELIEVE THE MEL HAD BEEN CONSULTED. EXPERIENCED FE ASSURED CAPT THAT MEL HAD BEEN COMPLIED WITH. CAPT DID NOT TRUST HIS 'GUT INSTINCT' THAT THESE 2 ITEMS CONFLICTED. SUPPLEMENTAL INFO FROM ACN 460828: THE SO CHKED THE MEL; FUEL DUMP; ITEM; WHICH DID NOT CONTAIN ANY REF TO THE INOP FUEL GAUGE. THE INOP FUEL GAUGE IN THE MEL; HOWEVER; DID REQUIRE THAT THE FUEL DUMP MUST BE WORKING. APPARENTLY HE MISSED THIS RESTR. SUPPLEMENTAL INFO FROM ACN 460555: OUR CREW DISCUSSED THE POSSIBILITY OF DUMPING IN AN EXTREME EMER; BASED ON THE WRITE-UP. WE ALSO DISCUSSED ALL THE REMARKS OF BOTH ITEMS. THE QTY GAUGE ITEM REQUIRES THE FUEL DUMP SYS OPERATE NORMALLY AND PROCS ARE ESTABLISHED...IF FUEL DUMPING IS REQUIRED; AND FUEL FLOW INDICATOR OPERATES NORMALLY. FUEL FLOW INDICATORS WERE VERIFIED GOOD AND DUMPING WAS MISTAKENLY ASSUMED TO NOT BE REQUIRED. WITH THAT ASSUMPTION AND THE FACT THAT THE PLANE HAD JUST FLOWN; NO CONFLICT SEEMED TO EXIST. POSSIBLE CORRECTIVE ACTIONS COULD INCLUDE ADDING TO THE REMARKS SECTIONS OF FUEL DUMP SYS 'ALL MAIN TANK FUEL QTY INDICATORS OPERATE NORMALLY.'