Narrative:

Preflight and flight planning were normal for this flight. One MEL deferral was given for 'stat' message 'lavatory galley fan right.' takeoff was normal with no adverse noise or control problems. Climb out was normal with the exception that at approximately 10000 ft MSL, first officer commented that '...this is a loud airplane in the cockpit.' this was an air noise, not engine, and crew's thinking was that the MEL might be related. Leveloff was at FL330. Both pilots noticed that left engine vibration was higher (2.8) than right (0.7). Within 15 mins, purser called cockpit to advise that there was a loud vibration on left engine side of aircraft. At this point, we were 5-15 mins past tusky. Cockpit crew immediately sent ACARS message to maintenance advising of left engine vibration and noise in cabin. After approximately 7 mins, we received a message from maintenance: 'vibes look excessive from our point of view, I suggest returning to jfk. Contact me via comrdo for additional information.' we attempted and accomplished satphone call to maintenance. After discussion with maintenance about engine indications and information that only he had access to, we asked him if he thought we should land earlier than jfk, and his response was no, they wanted us to return to jfk. We then asked him to patch us through to dispatch and he did. After discussion with dispatch, we received an ATC clearance back to jfk via tusky. Descent en route to jfk crew, dispatch and company maintenance discussed options of landing overweight or dumping fuel. Runway limit weights, landing data, WX were all checked and crew decision was to jettison fuel to 52000 pounds in descent, so that landing weight would be 445000 pounds or less. Descent was normal and a flaps 30 degree landing was accomplished on runway 31R jfk. Supplemental information from acn 615381: purser advised that he had to relocate a passenger to a different seat due to vibration of the passenger seat. Callback conversation with reporter revealed the following information: the reporter stated the left engine vibration indication was out of limits and the noise in the forward cabin was annoying and distracting. The reporter said the engine was not shut down. The reporter stated that fuel was dumped to maximum landing weight and landing was normal. The reporter said the engine was changed in the diverting station.

Related reports:

Google
 

Original NASA ASRS Text

Title: FLT CREW OF B777-200 ENCOUNTER EXCESSIVE VIBRATION LEVELS FROM L ENG SHORTLY AFTER DEP OUT OF JFK. DUMP FUEL AND RETURN FOR MAINT.

Narrative: PREFLT AND FLT PLANNING WERE NORMAL FOR THIS FLT. ONE MEL DEFERRAL WAS GIVEN FOR 'STAT' MESSAGE 'LAVATORY GALLEY FAN R.' TKOF WAS NORMAL WITH NO ADVERSE NOISE OR CTL PROBS. CLBOUT WAS NORMAL WITH THE EXCEPTION THAT AT APPROX 10000 FT MSL, FO COMMENTED THAT '...THIS IS A LOUD AIRPLANE IN THE COCKPIT.' THIS WAS AN AIR NOISE, NOT ENG, AND CREW'S THINKING WAS THAT THE MEL MIGHT BE RELATED. LEVELOFF WAS AT FL330. BOTH PLTS NOTICED THAT L ENG VIBRATION WAS HIGHER (2.8) THAN R (0.7). WITHIN 15 MINS, PURSER CALLED COCKPIT TO ADVISE THAT THERE WAS A LOUD VIBRATION ON L ENG SIDE OF ACFT. AT THIS POINT, WE WERE 5-15 MINS PAST TUSKY. COCKPIT CREW IMMEDIATELY SENT ACARS MESSAGE TO MAINT ADVISING OF L ENG VIBRATION AND NOISE IN CABIN. AFTER APPROX 7 MINS, WE RECEIVED A MESSAGE FROM MAINT: 'VIBES LOOK EXCESSIVE FROM OUR POINT OF VIEW, I SUGGEST RETURNING TO JFK. CONTACT ME VIA COMRDO FOR ADDITIONAL INFO.' WE ATTEMPTED AND ACCOMPLISHED SATPHONE CALL TO MAINT. AFTER DISCUSSION WITH MAINT ABOUT ENG INDICATIONS AND INFO THAT ONLY HE HAD ACCESS TO, WE ASKED HIM IF HE THOUGHT WE SHOULD LAND EARLIER THAN JFK, AND HIS RESPONSE WAS NO, THEY WANTED US TO RETURN TO JFK. WE THEN ASKED HIM TO PATCH US THROUGH TO DISPATCH AND HE DID. AFTER DISCUSSION WITH DISPATCH, WE RECEIVED AN ATC CLRNC BACK TO JFK VIA TUSKY. DSCNT ENRTE TO JFK CREW, DISPATCH AND COMPANY MAINT DISCUSSED OPTIONS OF LNDG OVERWT OR DUMPING FUEL. RWY LIMIT WTS, LNDG DATA, WX WERE ALL CHKED AND CREW DECISION WAS TO JETTISON FUEL TO 52000 LBS IN DSCNT, SO THAT LNDG WT WOULD BE 445000 LBS OR LESS. DSCNT WAS NORMAL AND A FLAPS 30 DEG LNDG WAS ACCOMPLISHED ON RWY 31R JFK. SUPPLEMENTAL INFO FROM ACN 615381: PURSER ADVISED THAT HE HAD TO RELOCATE A PAX TO A DIFFERENT SEAT DUE TO VIBRATION OF THE PAX SEAT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE L ENG VIBRATION INDICATION WAS OUT OF LIMITS AND THE NOISE IN THE FORWARD CABIN WAS ANNOYING AND DISTRACTING. THE RPTR SAID THE ENG WAS NOT SHUT DOWN. THE RPTR STATED THAT FUEL WAS DUMPED TO MAX LNDG WT AND LNDG WAS NORMAL. THE RPTR SAID THE ENG WAS CHANGED IN THE DIVERTING STATION.

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.