Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 250; Flight Crew Total 12000; Flight Crew Type 4000
Human-Machine Interface; Confusion
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft; Procedure; Human Factors
Fuel system synoptic showed fuel flowing from main tank 2 override pumps despite pumps being turned off (feeding tank to engine). Also showed no fuel flowing from any other center source (main 2 or 3) despite both eng pumps in mains 2 and 3 being selected on. Obviously no fuel was being supplied by ovrd pumps due to symmetrical fuel usage from main tanks 2 and 3. Issue corresponded to a CMC [Central Maintenance Computer] message indicating 'fuel supplied from fwd main 2 ovrd pump despite switch off.' That message was dated the day before we departed. Since the CMC is not a pilot preflight item; but is required of Maintenance; it seems someone should have caught that prior to our flight. Had the fuel actually been fed by an override pump that could not be turned off; we could have had a severe fuel balance issue. Also could have resulted in yet another large aircraft stuck in an out station requiring involved Maintenance. Seems like a trend lately.
A B747-400 flight crew noticed that; although the fuel synoptic was indicating fuel to all four engines was being delivered from main tank number 2--despite both override pumps being off--that fuel was being burned per the normal fuel management schedule.  They then discovered that the Central Maintenance Computer had noted the display fault the previous day; but the anomaly had not been addressed by Maintenance.