Narrative:

The first officer was flying and I was running the radios. Both relief pilots left the cockpit as we climbed out of 18300 ft. We got a call from one of the relief pilots stating that a flight attendant witnessed sparks coming out of the right engine during the climb. However the relief pilot didn't see anything unusual at the time. In the cockpit we didn't have any indication of any abnormal engine operation. The aircraft seemed to be operating normally without any vibration. We were level at FL250 and in contact with ATC. Perhaps 5-10 mins passed when we had 'banging' and vibration coming from the right engine. Engine instrument indications confirmed the right engine was surging. I informed ATC that we had a problem and that we would let them know more information as we dealt with the situation. ATC cooperated fully. I told the first officer to continue flying and I would run the checklists. During the right engine compressor stall checklist; the relief pilots returned to the cockpit. One of them stated that she saw a 10 ft flame emitted from the right engine. Since we had a full complement of crew members present; one of the relief pilots took the radio calls and backed up the PF while the other relief pilot backed me up while I ran the checklist. The relief pilot backing me made a satcom call to dispatch. After getting dispatch on the phone he requested maintenance to also be in on the call. When maintenance got on the phone I explained the problem as compressor stalling and vibration. Maintenance didn't seem to have any indication of anything abnormal. I explained that after following the checklist that we would get compressor stalling after the engine was accelerated slowly from idle to just over 50% N1 and the compressor stalling continued until the engine was returned to idle at which point the engine would operate normally without compressor stalling. Maintenance agreed that we should operate the engine at idle and not shut it down. Dispatch gave us ZZZZ1 or ZZZZ2 as alternates and I elected to divert to ZZZZ2. During this time the flying first officer requested FL190 due to aircraft performance. Dispatch checked performance numbers regarding our weight and confirmed that we met performance criteria even at our weight of approximately 566000 pounds. Obviously structural weight restrs would be exceeded but the dispatcher agreed with me that dumping of fuel would not be required. After finishing the satcom call; I informed ATC that we were declaring an emergency and requested clearance to ZZZZ2. Clearance was given without delay. I informed the crew that I would make the landing. A relief pilot got the ATIS. We were surprised that the winds were 30+ KTS gusting to 41 KTS. We were committed now and after calculating the crosswind landing wind component of 20 KTS; we felt that it was satisfactory. During this period one of the relief pilots informed the flight attendants and the passenger of our decision. The flight attendants made a cabin advisory. I briefed the approach and took the controls becoming the PF. We were cleared direct to the IAF and flew the approach on autoplt and autothrottle to approximately 1000 ft when I disengaged the autoplt. By this time the wind speeds had dropped down into the 20 KT range and the ride was smooth. The aircraft touched down at about a 320 FPM rate and at an indicated speed of 172 KTS; flaps 20 degrees. A normal rollout followed with autobrakes at level 3. We exited the runway without any complication and taxied to the gate.

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Original NASA ASRS Text

Title: B777 FLT CREW HAS ENG COMPRESSOR STALL AT ALT; DECLARES EMER AND DIVERTS FOR LNDG.

Narrative: THE FO WAS FLYING AND I WAS RUNNING THE RADIOS. BOTH RELIEF PLTS LEFT THE COCKPIT AS WE CLBED OUT OF 18300 FT. WE GOT A CALL FROM ONE OF THE RELIEF PLTS STATING THAT A FLT ATTENDANT WITNESSED SPARKS COMING OUT OF THE R ENG DURING THE CLB. HOWEVER THE RELIEF PLT DIDN'T SEE ANYTHING UNUSUAL AT THE TIME. IN THE COCKPIT WE DIDN'T HAVE ANY INDICATION OF ANY ABNORMAL ENG OP. THE ACFT SEEMED TO BE OPERATING NORMALLY WITHOUT ANY VIBRATION. WE WERE LEVEL AT FL250 AND IN CONTACT WITH ATC. PERHAPS 5-10 MINS PASSED WHEN WE HAD 'BANGING' AND VIBRATION COMING FROM THE R ENG. ENG INST INDICATIONS CONFIRMED THE R ENG WAS SURGING. I INFORMED ATC THAT WE HAD A PROB AND THAT WE WOULD LET THEM KNOW MORE INFO AS WE DEALT WITH THE SITUATION. ATC COOPERATED FULLY. I TOLD THE FO TO CONTINUE FLYING AND I WOULD RUN THE CHKLISTS. DURING THE R ENG COMPRESSOR STALL CHKLIST; THE RELIEF PLTS RETURNED TO THE COCKPIT. ONE OF THEM STATED THAT SHE SAW A 10 FT FLAME EMITTED FROM THE R ENG. SINCE WE HAD A FULL COMPLEMENT OF CREW MEMBERS PRESENT; ONE OF THE RELIEF PLTS TOOK THE RADIO CALLS AND BACKED UP THE PF WHILE THE OTHER RELIEF PLT BACKED ME UP WHILE I RAN THE CHKLIST. THE RELIEF PLT BACKING ME MADE A SATCOM CALL TO DISPATCH. AFTER GETTING DISPATCH ON THE PHONE HE REQUESTED MAINT TO ALSO BE IN ON THE CALL. WHEN MAINT GOT ON THE PHONE I EXPLAINED THE PROB AS COMPRESSOR STALLING AND VIBRATION. MAINT DIDN'T SEEM TO HAVE ANY INDICATION OF ANYTHING ABNORMAL. I EXPLAINED THAT AFTER FOLLOWING THE CHKLIST THAT WE WOULD GET COMPRESSOR STALLING AFTER THE ENG WAS ACCELERATED SLOWLY FROM IDLE TO JUST OVER 50% N1 AND THE COMPRESSOR STALLING CONTINUED UNTIL THE ENG WAS RETURNED TO IDLE AT WHICH POINT THE ENG WOULD OPERATE NORMALLY WITHOUT COMPRESSOR STALLING. MAINT AGREED THAT WE SHOULD OPERATE THE ENG AT IDLE AND NOT SHUT IT DOWN. DISPATCH GAVE US ZZZZ1 OR ZZZZ2 AS ALTERNATES AND I ELECTED TO DIVERT TO ZZZZ2. DURING THIS TIME THE FLYING FO REQUESTED FL190 DUE TO ACFT PERFORMANCE. DISPATCH CHKED PERFORMANCE NUMBERS REGARDING OUR WT AND CONFIRMED THAT WE MET PERFORMANCE CRITERIA EVEN AT OUR WT OF APPROX 566000 LBS. OBVIOUSLY STRUCTURAL WT RESTRS WOULD BE EXCEEDED BUT THE DISPATCHER AGREED WITH ME THAT DUMPING OF FUEL WOULD NOT BE REQUIRED. AFTER FINISHING THE SATCOM CALL; I INFORMED ATC THAT WE WERE DECLARING AN EMER AND REQUESTED CLRNC TO ZZZZ2. CLRNC WAS GIVEN WITHOUT DELAY. I INFORMED THE CREW THAT I WOULD MAKE THE LNDG. A RELIEF PLT GOT THE ATIS. WE WERE SURPRISED THAT THE WINDS WERE 30+ KTS GUSTING TO 41 KTS. WE WERE COMMITTED NOW AND AFTER CALCULATING THE XWIND LNDG WIND COMPONENT OF 20 KTS; WE FELT THAT IT WAS SATISFACTORY. DURING THIS PERIOD ONE OF THE RELIEF PLTS INFORMED THE FLT ATTENDANTS AND THE PAX OF OUR DECISION. THE FLT ATTENDANTS MADE A CABIN ADVISORY. I BRIEFED THE APCH AND TOOK THE CTLS BECOMING THE PF. WE WERE CLRED DIRECT TO THE IAF AND FLEW THE APCH ON AUTOPLT AND AUTOTHROTTLE TO APPROX 1000 FT WHEN I DISENGAGED THE AUTOPLT. BY THIS TIME THE WIND SPDS HAD DROPPED DOWN INTO THE 20 KT RANGE AND THE RIDE WAS SMOOTH. THE ACFT TOUCHED DOWN AT ABOUT A 320 FPM RATE AND AT AN INDICATED SPD OF 172 KTS; FLAPS 20 DEGS. A NORMAL ROLLOUT FOLLOWED WITH AUTOBRAKES AT LEVEL 3. WE EXITED THE RWY WITHOUT ANY COMPLICATION AND TAXIED TO THE GATE.

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.