Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Air Traffic Control Provided Assistance; Flight Crew FLC Overrode Automation; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Procedure
Throughout the flight the fuel score on the master flight plan was trending down. Approximately 1 hour into the flight we were down 1;000 lbs. on the fuel score. Winds were as forecasted. We then checked prog P2 and totalizer was 1.4 below calculated with a continuing trend down. We called the onboard mechanics up to discuss the issue. A call was also made to dispatch and maintenance control. No resolution was identified. No ICAS message had yet appeared but decided to run the 'FUEL CONFIGURATION' checklist from the QRH which led us to the 'FUEL LEAK ENGINE' checklist. Neither led to a satisfactory resolution. We discussed a pressure switch that was replaced in ZZZ with the onboard mechanic and decided to turn off the left center pump. This stopped the continuing fuel loss on the totalizer at 1.9. However with the right center pump providing fuel to the right engine we needed to keep it balanced by opening the transfer valves and turning off the left engine fuel pumps. (there was no fuel migration until this point from center to ether main tanks) After once again contacting dispatch and maintenance control with no resolution available and operating the fuel system in a non normal configuration I made the decision to return to ZZZ. The remainder of the flight continued normally and landed in ZZZ with approximately 70.0 Ibs of fuel and 2.5 low on the totalizer. I want to ad that the operating First Officer and the onboard mechanics were a tremendous help in trouble shooting and a satisfactory outcome. Also the other 2 crew members were brought into the decision making process.
Captain reported an air turnback after fuel score indicated a possible loss of fuel.