Narrative:

About 50 to 55 minutes into what was a routine flight to that point; we received a call from a flight attendant at door 2L stating that there was smoke coming from an overhead vent in the aft galley and a strong smell of electrical smoke. I immediately turned off both utility bus switches and called for the smoke/fire/fumes emergency QRH. A few minutes later; the flight attendant in the back said the smoke had stopped coming out of the overhead vent; but there was still a strong smell of electrical smoke odor. At this point; I considered the strong electrical smoke odor was residual and that tuning off the utility buses stopped the problem. I knew that we would not make it to europe with the utility buses off and that we would have to find a place to land. There was no way I was going to turn the utility buses back on in flight. If the source could be confirmed; I considered trying to return to the departure airport for further investigation. However; we were prepared to divert if the situation warranted. I sent dispatch a message and he came up shortly thereafter on satcom. I told him the problem that we were having and I thought he could get the help of maintenance control. When I turned off the utility buses; the relief first officer's attention was aroused since everything in the cabin turned off. He got up and went back to the aft galley to investigate. At first; he did not detect the odor. However; shortly afterwards; he said that there was a strong electrical smoke odor and that it came and went in waves. This report from the first officer really concerned me. I did not know if we had something smoldering and since we could not see it; I felt at this point it was prudent to get the airplane on the ground quickly. I told the first officer to declare an emergency with ATC and get the plane headed towards ZZZZ. This was just prior to maintenance control coming up on the line with dispatch. When he did come up on the satcom; I told him what was happening and that we had just made the decision to divert to ZZZZ. He asked me a few questions. Then dispatch asked me if we wanted to declare an emergency. I told him that we had already done that with ATC only about a minute or so prior. I asked dispatch for landing data for ZZZZ. I had the relief first officer come back to the flight deck and asked him to check our landing performance from the flight manual since we had a change in runways at ZZZZ. We also sent an update to dispatch. I told the chief purser to not plan on an evacuation; but to mentally prepare in case events got worse. The question about whether to dump fuel or not came up at some point early in the descent. I chose not to dump fuel. We weighed about 352.0 for landing and we had about 6;000 pounds in the center tank. Even if I had dumped the entire center tank; the approach speed would have only been 1 or 2 knots less and we had plenty of performance pad in both runway limit weight (better than 407.9) and performance limit weight which was at least 400.0. We touched down at ZZZZ 19 or 20 minutes after declaring an emergency. I elected to use level 3 auto brakes in order to try to keep the heating relatively even across both left and right landing gear. The fire trucks did not see anything unusual on the exterior of the aircraft after landing; so we proceeded to the gate.

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Original NASA ASRS Text

Title: B767-300 flight crew is informed of smoke in the aft galley by a Flight Attendant. The utility buses are turned off and QRH procedures complied with. While the visible smoke dissipates the odor persists and the crew elects to divert to the nearest suitable airport after declaring an emergency.

Narrative: About 50 to 55 minutes into what was a routine flight to that point; we received a call from a Flight Attendant at door 2L stating that there was smoke coming from an overhead vent in the aft galley and a strong smell of electrical smoke. I immediately turned off both utility bus switches and called for the Smoke/Fire/Fumes Emergency QRH. A few minutes later; the Flight Attendant in the back said the smoke had stopped coming out of the overhead vent; but there was still a strong smell of electrical smoke odor. At this point; I considered the strong electrical smoke odor was residual and that tuning off the utility buses stopped the problem. I knew that we would not make it to Europe with the utility buses off and that we would have to find a place to land. There was no way I was going to turn the utility buses back on in flight. If the source could be confirmed; I considered trying to return to the departure airport for further investigation. However; we were prepared to divert if the situation warranted. I sent Dispatch a message and he came up shortly thereafter on SATCOM. I told him the problem that we were having and I thought he could get the help of Maintenance Control. When I turned off the utility buses; the Relief First Officer's attention was aroused since everything in the cabin turned off. He got up and went back to the aft galley to investigate. At first; he did not detect the odor. However; shortly afterwards; he said that there was a strong electrical smoke odor and that it came and went in waves. This report from the First Officer really concerned me. I did not know if we had something smoldering and since we could not see it; I felt at this point it was prudent to get the airplane on the ground quickly. I told the First Officer to declare an emergency with ATC and get the plane headed towards ZZZZ. This was just prior to Maintenance Control coming up on the line with Dispatch. When he did come up on the SATCOM; I told him what was happening and that we had just made the decision to divert to ZZZZ. He asked me a few questions. Then Dispatch asked me if we wanted to declare an emergency. I told him that we had already done that with ATC only about a minute or so prior. I asked Dispatch for landing data for ZZZZ. I had the Relief First Officer come back to the flight deck and asked him to check our landing performance from the flight manual since we had a change in runways at ZZZZ. We also sent an update to Dispatch. I told the Chief Purser to not plan on an evacuation; but to mentally prepare in case events got worse. The question about whether to dump fuel or not came up at some point early in the descent. I chose not to dump fuel. We weighed about 352.0 for landing and we had about 6;000 LBS in the center tank. Even if I had dumped the entire center tank; the approach speed would have only been 1 or 2 knots less and we had plenty of performance pad in both runway limit weight (better than 407.9) and performance limit weight which was at least 400.0. We touched down at ZZZZ 19 or 20 minutes after declaring an emergency. I elected to use level 3 auto brakes in order to try to keep the heating relatively even across both left and right landing gear. The fire trucks did not see anything unusual on the exterior of the aircraft after landing; so we proceeded to the gate.

Data retrieved from NASA's ASRS site as of April 2012 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.