Flight Crew Air Transport Pilot (ATP)
Troubleshooting
Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue
Flight Crew Diverted
Aircraft
We were very heavy at 200;000 LBS takeoff. It took us a long time to get to cruise. At first HEFOE check after reaching cruise altitude; realized the possibility there was a fuel transfer issue with Auxiliary Center Tanks (ACT). Observed fuel system display for 10-15 minutes until verifying that fuel was not transferring to center tank.Contacted dispatch and maintenance. Activated manual ACT pump override. Fuel from FWD ACT (left ACT on system display) began to transfer. Dispatch; with maintenance concurrence; said to continue. 30-40 minutes later the FWD ACT was empty. Unfortunately; the AFT ACT tank did not transfer its fuel with the secondary pump. Once again; we contacted dispatch advising them we would have to land with almost 4000 LBS in the aft ACT.Dispatch requested we divert. We took delaying vectors in order to land under max landing weight. We landed 25 minutes later at 171;000 lbs. We switched aircraft and continued uneventfully to our scheduled destination.
A321 Captain reported the Additional Center Tank aft did not transfer properly. Flight diverted to interim airport.