Narrative:

Departure; climb out and coastout was uneventful. While cruising at FL360 the cabin got quieter due to fans shutting off; and noticed my navigation display blank momentarily. Quickly had several EICAS messages for fuel pump; hydraulic C2 pump; window heat and pitot heat; but no electrical EICAS messages. We looked at the electrical synoptic and noted that the right main bus was amber and not pwred. The right xfer bus was pwred by the right backup generator. We started the APU; but it would not power the right main bus; and the bus tie remained open. Through all of this there were no lights or abnormal indications at all on the overhead electrical panel. Within about 2 mins we started smelling smoke in the cockpit and called the cabin where they were also now smelling smoke in 1ST class. We made the decision to return to ZZZ and made request through cpdlc. Oceanic came back with a clearance to descend straight ahead to FL290 and report level for clearance to turn. After level at FL290; they gave clearance to proceed direct ZZZ. Shortly after turning around the smoke smell returned and was now throughout the cabin. It once again dissipated. Smoke was never visible and did not get to be strong intensity. The smoke and fumes qrc was looked at for reference if needed; but never got to the point where that checklist was run. We got dispatch and maintenance on the satcom; and maintenance recommended that we not attempt to recycle any electrical switches given our indications. An in-flight emergency was declared on cpdlc to ensure traffic priority. We got in VHF contact with center and were cleared direct to ZZZ. We also got descent clearance down to FL250 and attempted to dump 25000 pounds of fuel so as to be below an overweight landing. When we attempted to jettison fuel; the right jettison pump was inoperative (due to electric problem most likely); and the left jettison pump failed shortly after starting to dump. Perhaps 1000 pounds of fuel were jettison. At that point a flaps 30 degree overweight landing was planned; and dispatch checked landing performance weights. The overweight landing checklist was run. Actual landing fuel was 57.0 with a 407.0 ZFW giving a landing weight of 464. Flight attendants were given a cabin advisory and briefed of arrival time and expected normal taxi in. We requested the longer runway at ZZZ and configured early to burn more fuel and also ensure that confign would be normal. Approach and landing were uneventful. Fire trucks were standing by and followed the aircraft towards the gate with nothing abnormal reported. We taxied into the gate; and maintenance could smell smoke from the outside of the aircraft. They recommended that we immediately depower the aircraft; which we did. The passenger left the unpowered airplane; via the normal jetway. Cargo doors had to be cranked open to unload baggage.

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Original NASA ASRS Text

Title: B777-200 RIGHT MAIN ELECTRICAL BUS FAILED; ACCOMPANIED BY THE SMELL OF SMOKE. FLT CREW DECLARED AN EMER AND RETURNED TO DEP ARPT.

Narrative: DEP; CLBOUT AND COASTOUT WAS UNEVENTFUL. WHILE CRUISING AT FL360 THE CABIN GOT QUIETER DUE TO FANS SHUTTING OFF; AND NOTICED MY NAV DISPLAY BLANK MOMENTARILY. QUICKLY HAD SEVERAL EICAS MESSAGES FOR FUEL PUMP; HYD C2 PUMP; WINDOW HEAT AND PITOT HEAT; BUT NO ELECTRICAL EICAS MESSAGES. WE LOOKED AT THE ELECTRICAL SYNOPTIC AND NOTED THAT THE R MAIN BUS WAS AMBER AND NOT PWRED. THE R XFER BUS WAS PWRED BY THE R BACKUP GENERATOR. WE STARTED THE APU; BUT IT WOULD NOT PWR THE R MAIN BUS; AND THE BUS TIE REMAINED OPEN. THROUGH ALL OF THIS THERE WERE NO LIGHTS OR ABNORMAL INDICATIONS AT ALL ON THE OVERHEAD ELECTRICAL PANEL. WITHIN ABOUT 2 MINS WE STARTED SMELLING SMOKE IN THE COCKPIT AND CALLED THE CABIN WHERE THEY WERE ALSO NOW SMELLING SMOKE IN 1ST CLASS. WE MADE THE DECISION TO RETURN TO ZZZ AND MADE REQUEST THROUGH CPDLC. OCEANIC CAME BACK WITH A CLRNC TO DSND STRAIGHT AHEAD TO FL290 AND RPT LEVEL FOR CLRNC TO TURN. AFTER LEVEL AT FL290; THEY GAVE CLRNC TO PROCEED DIRECT ZZZ. SHORTLY AFTER TURNING AROUND THE SMOKE SMELL RETURNED AND WAS NOW THROUGHOUT THE CABIN. IT ONCE AGAIN DISSIPATED. SMOKE WAS NEVER VISIBLE AND DID NOT GET TO BE STRONG INTENSITY. THE SMOKE AND FUMES QRC WAS LOOKED AT FOR REF IF NEEDED; BUT NEVER GOT TO THE POINT WHERE THAT CHKLIST WAS RUN. WE GOT DISPATCH AND MAINT ON THE SATCOM; AND MAINT RECOMMENDED THAT WE NOT ATTEMPT TO RECYCLE ANY ELECTRICAL SWITCHES GIVEN OUR INDICATIONS. AN INFLT EMER WAS DECLARED ON CPDLC TO ENSURE TFC PRIORITY. WE GOT IN VHF CONTACT WITH CTR AND WERE CLRED DIRECT TO ZZZ. WE ALSO GOT DSCNT CLRNC DOWN TO FL250 AND ATTEMPTED TO DUMP 25000 LBS OF FUEL SO AS TO BE BELOW AN OVERWT LNDG. WHEN WE ATTEMPTED TO JETTISON FUEL; THE R JETTISON PUMP WAS INOP (DUE TO ELECTRIC PROB MOST LIKELY); AND THE L JETTISON PUMP FAILED SHORTLY AFTER STARTING TO DUMP. PERHAPS 1000 LBS OF FUEL WERE JETTISON. AT THAT POINT A FLAPS 30 DEG OVERWT LNDG WAS PLANNED; AND DISPATCH CHKED LNDG PERFORMANCE WTS. THE OVERWT LNDG CHKLIST WAS RUN. ACTUAL LNDG FUEL WAS 57.0 WITH A 407.0 ZFW GIVING A LNDG WT OF 464. FLT ATTENDANTS WERE GIVEN A CABIN ADVISORY AND BRIEFED OF ARR TIME AND EXPECTED NORMAL TAXI IN. WE REQUESTED THE LONGER RWY AT ZZZ AND CONFIGURED EARLY TO BURN MORE FUEL AND ALSO ENSURE THAT CONFIGN WOULD BE NORMAL. APCH AND LNDG WERE UNEVENTFUL. FIRE TRUCKS WERE STANDING BY AND FOLLOWED THE ACFT TOWARDS THE GATE WITH NOTHING ABNORMAL RPTED. WE TAXIED INTO THE GATE; AND MAINT COULD SMELL SMOKE FROM THE OUTSIDE OF THE ACFT. THEY RECOMMENDED THAT WE IMMEDIATELY DEPOWER THE ACFT; WHICH WE DID. THE PAX LEFT THE UNPOWERED AIRPLANE; VIA THE NORMAL JETWAY. CARGO DOORS HAD TO BE CRANKED OPEN TO UNLOAD BAGGAGE.

Data retrieved from NASA's ASRS site as of January 2009 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.