Narrative:

En route ZZZ-hng FL350, so noticed #3 engine losing oil 1.0 to 1.5 gph. So monitored engine #3 oil quantity and it continued to decrease. Advised company maintenance control. They suggested monitoring the engine closely. When oil quantity reached zero, crew decided to land at san francisco and not proceed overwater into a likely 3-ENG scenario. Oil quantity continued to drop. Received clearance to descend to FL240 and proceed direct san francisco. Coordination with cabin crew to land in 25-30 mins. Aircraft weight approximately 600000 pounds. No fuel dump necessary. During descent, sfo approach control declared emergency for the aircraft. Captain and first officer noticed oily smell in cockpit and flight attendant called forward stating oil appeared to be leaking onto #3 engine cowl, and onto aircraft windows on right side of aircraft aft of wing. Crew immediately requested expedited descent and priority handling. So communicated this update to cabin crew, indicating landing was now 5-10 mins away. Appropriate checklists completed. Aircraft cleared to, and established on final approach approximately 3000-4000 ft and 8-10 mi from airport, insufficient altitude and time remaining to dump fuel. Aircraft made very smooth and uneventful landing, rollout and taxi in. Aircraft landed 7000 pounds overweight. Taxied to gate. Sfo maintenance troubleshot #3 engine. Could not determine source of leak. Maintenance also performed overweight landing inspection, and pronounced aircraft 'safe for flight.' maintenance issued ferry permit and maintenance control order for ferry flight back to ZZZ. Crew ferried aircraft to ZZZ. Uneventful flight, except for slight oil loss on #3 engine, about 1 gph. Sfo approach had declared emergency situation for the aircraft prior to approach and landing back at sfo.

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Original NASA ASRS Text

Title: B747-200 CREW WAS LOSING OIL FROM #3 ENG IN ZLC CLASS A AIRSPACE.

Narrative: ENRTE ZZZ-HNG FL350, SO NOTICED #3 ENG LOSING OIL 1.0 TO 1.5 GPH. SO MONITORED ENG #3 OIL QUANTITY AND IT CONTINUED TO DECREASE. ADVISED COMPANY MAINT CTL. THEY SUGGESTED MONITORING THE ENG CLOSELY. WHEN OIL QUANTITY REACHED ZERO, CREW DECIDED TO LAND AT SAN FRANCISCO AND NOT PROCEED OVERWATER INTO A LIKELY 3-ENG SCENARIO. OIL QUANTITY CONTINUED TO DROP. RECEIVED CLRNC TO DSND TO FL240 AND PROCEED DIRECT SAN FRANCISCO. COORD WITH CABIN CREW TO LAND IN 25-30 MINS. ACFT WT APPROX 600000 LBS. NO FUEL DUMP NECESSARY. DURING DSCNT, SFO APCH CTL DECLARED EMER FOR THE ACFT. CAPT AND FO NOTICED OILY SMELL IN COCKPIT AND FLT ATTENDANT CALLED FORWARD STATING OIL APPEARED TO BE LEAKING ONTO #3 ENG COWL, AND ONTO ACFT WINDOWS ON R SIDE OF ACFT AFT OF WING. CREW IMMEDIATELY REQUESTED EXPEDITED DSCNT AND PRIORITY HANDLING. SO COMMUNICATED THIS UPDATE TO CABIN CREW, INDICATING LNDG WAS NOW 5-10 MINS AWAY. APPROPRIATE CHKLISTS COMPLETED. ACFT CLRED TO, AND ESTABLISHED ON FINAL APCH APPROX 3000-4000 FT AND 8-10 MI FROM ARPT, INSUFFICIENT ALT AND TIME REMAINING TO DUMP FUEL. ACFT MADE VERY SMOOTH AND UNEVENTFUL LNDG, ROLLOUT AND TAXI IN. ACFT LANDED 7000 LBS OVERWT. TAXIED TO GATE. SFO MAINT TROUBLESHOT #3 ENG. COULD NOT DETERMINE SOURCE OF LEAK. MAINT ALSO PERFORMED OVERWT LNDG INSPECTION, AND PRONOUNCED ACFT 'SAFE FOR FLT.' MAINT ISSUED FERRY PERMIT AND MAINT CTL ORDER FOR FERRY FLT BACK TO ZZZ. CREW FERRIED ACFT TO ZZZ. UNEVENTFUL FLT, EXCEPT FOR SLIGHT OIL LOSS ON #3 ENG, ABOUT 1 GPH. SFO APCH HAD DECLARED EMER SIT FOR THE ACFT PRIOR TO APCH AND LNDG BACK AT SFO.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.