B747 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 100; Flight Crew Total 24000; Flight Crew Type 1200
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
Flight Crew Diverted
Aircraft
#4 fuel spar valve status message appeared on taxi out.  At cruise stab fuel transfer was initiated on schedule.  Approximately 5 minutes later EICAS annunciated 'FUEL IMBALANCE 1-4'.  Stab fuel quantity was 17.0 - fuel synoptic showed #4 tank 3;000 pounds less than #1 with #4 decreasing at a rate of 300-400 pounds / min. The irregular checklist for fuel imbalance did not seem to address our situation.Contacted [Maintenance Control] thru [Dispatch] for assistance. Aircraft seemed to be in trim when hand flown.  I elected to transfer the remaining stab fuel to the center tank since landing with stab fuel is problematic.  #4 fuel quantity continued to decrease during stab transfer and at completion was greater than 7;000 pound imbalance.  After consulting with [Maintenance Control] and [Dispatch] I decided a divert would be most prudent and have maintenance check the issue.  Fuel was dumped enroute in hopes of reaching landing weight at touchdown; however with an unknown quantity of fuel in #4 tank; landing weight was later found to be 632.0.  Maintenance drip sticked fuel on arrival and confirmed #4 fuel quantity was indicating correctly.
A B-747 Air Crew experienced an EICAS message warning of a fuel imbalance between tanks 1 and 4. They consulted with maintenance; dumped fuel; and diverted.