A B767-200 WAS DISPATCHED IN NON COMPLIANCE WITH AN INTEGRATED DRIVE GENERATOR OIL LEAK BEYOND THE MEL LIMITS.

Narrative

ON MAR/XA/99 AT ZY00Z; I RECEIVED A CALL FROM THE MAINT DEPT OF ACR AIRLINES IN ZZZ. THE CALL WAS IN REF TO AN OIL LEAK ON THE R-HAND ENG. THE OIL LEAK WAS DETACHED AS COMING FROM THE SEAL DRAIN OF THE INTEGRATED DRIVE GENERATOR. THE ACFT MAINT TECHNICIAN INFORMED ME THAT THE OIL LEAK WAS APPROX 10 DROPS PER MIN. LOOKING AT THE MAINT MANUAL I ASCERTAINED THAT THE ALLOWABLE LEAKAGE RATE WAS IN FACT 3 DROPS PER MIN. THE REF FOR THE LEAK RATE IS FOUND IN MAINT MANUAL XX-XX-YY PAGE 605. LOOKING AT THE NEXT PAGE THE TABLE HAS A NUMBER OF FOOTNOTES REGARDING EXTRA INFO IN DETERMINING THE DISPOSITION OF THE LEAK AND ITS RECTIFICATION. I MISTAKENLY LOOKED AT FOOTNOTE 3. THE NOTE ALLOWS A ONE TIME FLY-BACK LIMIT IN EXCESS OF THE 3 DROPS PER MIN NORMALLY ALLOWED. AS THE ACFT WAS PAST ITS SCHEDULED DEP TIME WITH PAX ALREADY BOARDED; I WAS HOPING THAT WE COULD IN FACT PRESERVE THE DEP AND ADDRESS THE LEAK AT A MORE CONVENIENT TIME. I MISTAKENLY ASSOCIATED THAT FOOTNOTE WITH THE INTEGRATED DRIVE GENERATOR ALLOWABLE LEAK RATE AND THEREFORE ALLOWED THE LEAK TO BE DEFERRED AND PLANNED FOR THE RECTIFICATION AT THE NEXT STATION; THUS MITIGATING ANY DISSERVICE TO OUR CUSTOMERS. UNFORTUNATELY; AS I LOOKED AT THE TABLE AGAIN AFTER ALLOWING THE DEFERRAL; I REALIZED THAT IN FACT THE FOOTNOTE DID NOT APPLY IN THIS SIT. THE ACFT HAD ALREADY DEPARTED AND I WAS UNABLE TO CORRECTLY ADDRESS THE LEAK. I THEN ARRANGED FOR THE LEAK TO BE RECTIFIED IN YYY -- THE NEXT DEST FOR THE ACFT. ON ARR; THE INTEGRATED DRIVE GENERATOR WAS IN FACT REPLACED AND THE CARBON SEAL ALSO. THE LEAK CAUSED NO INFLT OPERATIONAL DIFFICULTIES ON THE ZZZ TO YYY SECTOR. IT WAS MY DESIRE TO PRESERVE THE FLT THAT PROMPTED ME TO LOOK THROUGH THE TABLE OF ALLOWABLE LEAKS LOOKING FOR A REF THAT MAY BE USED IN THIS INSTANCE. THE NUMBERING SYS USED IN THE TABLE WAS WHERE I MADE MY MISTAKE APPLYING THE EXTRA LIMIT.