B767-400 and 400 ER
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 241; Flight Crew Total 25000; Flight Crew Type 6000
Training / Qualification; Troubleshooting; Workload
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
General None Reported / Taken
Aircraft; Procedure
During initial cruise with fuel in the center tank; the left tank had 2;000 LBS more than the right tank. Engine fuel flow and the PROG page 2 showed both engines using the same amount of fuel. The QRH Fuel Configuration procedure steps 3 and 4 setup the crossfeed but there is no step to turn off the center tank pumps. The center tank pumps will over pressure and prevent the crossfeed from occurring. This type of fuel imbalance is not an isolated occurrence on this type aircraft.
The Reporter stated that the normal fuel imbalance procedure is completed from memory. In this event; an FAA Inspector was in the jump seat; so when the Fuel Config annunciated; the First Officer referenced the QRH where two checklists were found. One was the Fuel Config and the second Fuel Crossfeed. The Fuel Config Checklist was followed but the crew soon realized that because the center tanks contained fuel and the pumps were ON; the checklist could not balance the tanks because the center pump overrode the wing tank pumps. So the Captain used his emergency authority and turned the center tank pumps OFF until the wing tanks were balanced. He later discovered that another Checklist in the Supplemental Manual covered this situation so he suggests including a step in the QRH Fuel Config procedure which references center tank pumps in the event they are ON and need to be turned OFF in order to keep the aircraft with limits.
A pilot reported that his aircraft's center tank fuel pumps overrode wing tank fuel pumps so when a wing tank fuel imbalance occurred no procedure was available to turn the center tank pumps OFF to balance wing tanks.