A WBD TRANSPORT OVERWATER FLT WAS CANCELED DUE TO A LEAKING BRAKE DEFERRED PER THE MEL. ACFT COULD NOT MEET OPERATING RESTRS IN MANUAL.

Narrative

FLT ZZZ-ZZZZ WAS ALREADY DELAYED DUE TO LATE INBOUND EQUIP. A HYD LEAK IN ONE OF THE BRAKES WAS DISCOVERED UPON ARR. TECHNICIAN SVCS CONTACTED ME FOR APPROVAL TO USE MEL 32-20B WHEEL BRAKES DEACTIVATED BY CAPPING THE LINE (1 BRAKE INOP). THEY WERE UNABLE TO USE 32-20A DUE TO THE LEAKAGE. I APPROVED AND PLACARDED BASED ON THE WT REDUCTION TABLE IN THE MEL MANUAL FOR 32-20B. I THEN TURNED COMPUTER LISTING LIMITS ON WHICH APPLIED A PENALTY OF 160000 LBS TO BOTH THE RWY LIMITED AND CLB LIMITED TKOF WT. I CONTACTED OPS ENGINEERING AND THEY SAID THAT THE 160000 LBS IS CORRECT DUE TO HAVING TO LEAVE THE GEAR DOWN FOR 2 MINS AFTER TKOF. THE MEL DOES REFER TO 'OM VOLUME #1; PERFORMANCE NON-NORMALS-GEAR DOWN OPS' WHERE THE CORRECT WT REDUCTIONS ARE FOUND. I CALLED TECHNICIAN BACK AND TOLD THEM THAT I WOULD HAVE TO DENY THE PLACARD DUE TO THE WT LIMITATION! THE ACFT WAS REMOVED FROM SVC AND THE FLT SUBSEQUENTLY CANCELLED. THE WT REDUCTION TABLE IN THE MEL MANUAL NEEDS TO ACCURATELY REFLECT THE RESTRS ON THE OPERATING MANUAL.