A300
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
Flight Crew Overcame Equipment Problem
Aircraft
Approximately [2 hours and 45 minutes] into flight we noticed that fuel was being burned from the outer tanks with fuel still in the inner tanks.  The outer tanks were showing about 7;000 pounds each. The center tank was empty and there was about 5;000 pounds of fuel in the trim tank.  There were no ECAM messages about this condition.  We cycled the center tank switches and the condition did not change.  The fuel in the trim tank was determined to be unusable if it was not pumped forward to the center tank.  We successfully pumped the trim tank fuel forward to the center tank.  At this point the center tank still failed to feed the engines using Auto Fuel Feed.  Manual fuel feed procedures were used and we were able to burn fuel from the center tank.  Prior to landing the center tank pumps were turned off to allow tank to engine fuel feeding.  It was determined during this process that enough fuel was present in the outer tanks to safely reach our destination.
A300 First Officer notices that fuel was being burned from the outer tanks with fuel still in the inner tanks. Trim tank fuel is manually transferred to the center tank then fed to the engines allowing the flight to continue to destination.