B787 Dreamliner Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 13846; Flight Crew Type 715
Confusion; Distraction; Workload
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Other / Unknown
Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Procedure
We tried to update the winds on our flight computer. When executed; we got an immediate Insufficient Fuel EICAS; and found the update had wiped out our previous winds obtained on the ground; and zeroed the descent winds. We tried again; and this time we got no winds AND an EICAS Autopilot message with LNAV and VNAV; and the LNAV and VNAV commands were lined through on the FLT DIR. We also got the status message Cruise Flap Disagree. The route on the HSI had converted to a dashed blue line. The last attempt at retrieving winds wiped out the route on the HSI with no markings or line. By then I had placed the aircraft in ALT HOLD and HDG SELECT to protect our position. The route was still in the flight computer so we were able to activate and execute it and got the route back; then reengaged LNAV. There was no course or altitude deviation during this incident. On further investigation; we found the normal preflight required loads on the PERF INIT page had been wiped out. We reinstalled the ZFW and Cost Index; and the cruise flap EICAS went away. The aircraft was restored to LNAV and VNAV and we manually installed the winds. We called the dispatcher and Maintenance Control and were told not to write this in the logbook but this incident needs to be disseminated to all pilots. The wind file had to be corrupted somehow; and in the 787 it also corrupted our flight computer with escalating damage. On my commute home; I sat next to [a] 777 Captain from an oceanic flight and they experienced something similar when they tried to upload the same winds; but their wind download just put all their enroute winds to zero. They were able to correct their problem by deleting the wind altitudes then re-requesting the winds and reloading. We were very lucky and were able to maintain course and altitude and recovered the aircraft quickly and without further incident; but there are so many ways this could have gone wrong. We were in VMC and in contact with Center and in radar control; so very lucky. We advised our relief crew not to update the winds 6 hours later unless they did it manually; to avoid any further issues. How did a simple wind download delete our computer data? How did a wind download kick off our route? Please ensure this is investigated.
B787 First Officer reported a faulty enroute oceanic wind update affected the FMC which resulted in an insufficient fuel alert; a cruise flap disagree and an LNAV/VNAV disconnect. A flight plan reinstall with manual winds corrected the fault.