Narrative:

On our flight to zspd; approximately 3 hours into the flight; we requested and loaded the [current] winds into the FMC. After we pushed the 'execute' button; we noticed our ETA on the progress page of the FMC pushed our arrival time back 30 minutes as well as decreasing our arrival fuel by 6;000 pounds. We thought this [to be] rather strange and requested and loaded the winds a second time. There was no change. After verifying the wind data against the flight plan; we determined there were sizable changes in the winds for the duration of the flight. However; based on some issues we had pre-departure with the flight plan; we were a little suspicious. Coincidently; another company flight to zspd was within a couple of miles of us the entire way. We asked him if he encountered any issues while loading the [current] winds. After they; too; loaded these winds; their arrival time also changed by 30 minutes and their arrival fuel also decreased by [about] 6;000 pounds. I spoke with dispatch about this to make sure we had a suitable plan in case our fuel score continued to deteriorate. During the final 8 hours of the flight; our ETA and arrival fuel on the progress page continued to incrementally change and eventually we landed at the exact time the progress page said we would with the fuel we would have prior to loading the [current] winds.

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Original NASA ASRS Text

Title: Air carrier Captain en route to ZSPD reports updating the FMC winds; which results in 30 minutes added to the ETA and 6;000 LBS less fuel at touch down. As the flight progresses; the ETA and fuel score gradually return to their pre-update values.

Narrative: On our flight to ZSPD; approximately 3 hours into the flight; we requested and loaded the [current] winds into the FMC. After we pushed the 'execute' button; we noticed our ETA on the progress page of the FMC pushed our arrival time back 30 minutes as well as decreasing our arrival fuel by 6;000 LBS. We thought this [to be] rather strange and requested and loaded the winds a second time. There was no change. After verifying the wind data against the flight plan; we determined there were sizable changes in the winds for the duration of the flight. However; based on some issues we had pre-departure with the flight plan; we were a little suspicious. Coincidently; another company flight to ZSPD was within a couple of miles of us the entire way. We asked him if he encountered any issues while loading the [current] winds. After they; too; loaded these winds; their arrival time also changed by 30 minutes and their arrival fuel also decreased by [about] 6;000 LBS. I spoke with Dispatch about this to make sure we had a suitable plan in case our fuel score continued to deteriorate. During the final 8 hours of the flight; our ETA and arrival fuel on the progress page continued to incrementally change and eventually we landed at the exact time the progress page said we would with the fuel we would have prior to loading the [current] winds.

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.