A DC10 FLC DECLARED AN EMER AND RETURNED TO LAND AFTER SMELLING ELECTRICAL SMOKE FUMES DURING THEIR DEP CLB; AT 14000 FT. THE FLC HAD ORIGINALLY DELAYED DEP FOR MAINT CONSULTATION REGARDING A DUCT OVERHEAT ANNUNCIATOR THAT WAS THEN DEFERRED BY MAINT. FOLLOW-UP MAINT INSPECTION REVEALED AN UNRELATED PROB OF AIR CYCLE MACHINE FUMES CAUSED BY A #1 ENG OIL LEAK.

Narrative

BEFORE DEPARTING CLE WE HAD A 'DUCT AVIONICS COMPARTMENT OVERHEAT' LIGHT COME ON. WE FOLLOWED THE IRREGULAR PROC AND THE LIGHT WENT OUT. MAINT WAS CALLED AND THEY DECIDED IT WAS OK TO DEPART. ON TAXI OUT THE OVERHEAT LIGHT CAME ON AGAIN AND BY FOLLOWING THE IRREGULAR PROCS AGAIN; IT WENT OUT. WE CALLED LINE MAINT AND BECAUSE WE HAD NO OTHER INDICATION OF AN OVERHEAT THEY DEFERRED THE LIGHT. WE DEPARTED CLE AND HAD CLBED TO 14000 FT WHEN WE SMELLED WHAT SEEMED TO BE ELECTRICAL SMOKE. AT THE SAME TIME FLT ATTENDANTS CALLED FROM THE AFT CABIN TO INFORM US THAT THEY SMELLED FUMES. SO WE AS A COCKPIT CREW QUICKLY DECIDED THAT UNDER THE CIRCUMSTANCES WE HAD BETTER RETURN TO CLE IMMEDIATELY! WE DECLARED AN EMER AND RETURNED TO CLE IN LESS THAN 10 MINS. EMER EQUIP WAS REQUESTED. ON THE DSCNT INTO CLE THE FUMES SEEMED TO BE REDUCED AND WE KNEW THAT WE WOULD HAVE A NORMAL LNDG; BUT WE ASKED THE EMER EQUIP PEOPLE TO CHK OUR ACFT FOR SMOKE AND OR FIRE WHEN WE TAXIED OFF THE RWY. THEY SAW NOTHING SO WE TAXIED TO THE GATE AND DEPLANED THE PEOPLE. LATER IT WAS DETERMINED THE CAUSE OF THE FUMES WAS OIL LEAKING FROM THE #1 ENG INTO THE HOT DUCTING THAT WAS PART OF THE RECYCLE MACHINE. (THE DUCT AVIONICS OVERHEAT LIGHT WAS UNRELATED.)