A B757 WAS DISPATCHED IN NON COMPLIANCE WITH A MAIN FUEL QUANTITY INDICATOR DEFERRED AS INOP; BUT IN CONFLICT WITH THE MEL.

Narrative

B757 TECH CALLED FOR A PLACARD JUST BEFORE DEP TIME FOR MEL 28-11A; MAIN TANK FUEL QUANTITY INDICATOR. AFTER READING MEL; I APPROVED THE PLACARD AND ADVISED TECHNICIAN THE ACFT WOULD HAVE TO BE FIXED IN ZZZ1 DUE TO THE 50 NM FROM LAND RESTR STATED IN THE MEL. MEL STATES 1 TANK INDICATOR MAY BE INOP FOR OPS NOT MORE THAN 50 NM FROM LAND IN THE 48 CONTIGUOUS STATES; CANADA; MEXICO; AND CENTRAL AMERICA. I STOPPED READING THERE AND APPROVED THE MEL. ABOUT 1 HR LATER; I RECEIVED A CALL FROM TECHNICIAN SAYING WE SHOULD HAVE NEVER LEFT ZZZ WITH THIS MEL. I MISSED THE STATEMENT THAT SAYS THEY MUST BE OPERATIVE FOR ALL OTHER OPS. I WAS UNDER THE IMPRESSION THAT SINCE WE WERE WITHIN 50 NM OF LAND FROM ZZZ-ZZZ1; THAT WE WERE FINE TO GO. BUT; AFTER READING THE MEL AGAIN; I DEFINITELY MISSED THE STATEMENT THAT THEY BOTH MUST BE OPERATIVE OUTSIDE THE DEFINED AREAS STATED IN MEL 28-11A. IT WAS AN OVERSIGHT ON MY PART AS WELL AS THE TECHNICIAN'S AND THE CAPT'S. I NEVER SHOULD HAVE BEEN CALLED FOR THE PLACARD; BUT I SHOULD HAVE READ ALL OF THE PROVISIONS OF THE MEL. I ALSO BELIEVE WE ARE HANDCUFFING OURSELVES IN PARTS OF THE CARIBBEAN WITH THIS MEL. MANY TIMES WE CAN STAY 50 NM FROM LAND IN THE ISLANDS.