B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
Air Traffic Control Issued New Clearance; Flight Crew Returned To Departure Airport; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
On climb out; the FO mentioned that the jet felt very out of trim. The FO was new to the airplane; and in particular the [older 737]. I stated that a bit out of trim was not unusual. As we leveled off at FL340; I took off the autopilot and attempted to trim the aircraft. It was very out of trim; and the jet was in a constant skid in level flight. I assured that all indications were symmetrical; matched thrust; heading selected and fuel balanced. After further discussion the FO stated he thought the jet was very out of trim from the initial takeoff. Because we departed in weather and turbulence; and due to the early morning departure; he thought it was just an issue with him being new to the [older 737]. The miss trim was not stated to me until approaching top of climb. We discussed the situation; and I stated that I would be writing the issue up; and that we should consult with Dispatch and Maintenance Control about a return. After discussing with both; we initiated a return. We had departed with a fuel load of 28;000 LBS; and were still burning out of the center tanks at the time of the return. Approximately 15 minutes after diverting; I noticed an FMC message 'check FMC fuel quantity'. I then checked the right fuel quantity indicator and it showed 5;880 LBS of fuel; and the left tank indicated 10;000 LBS of fuel. We ran the QRH for fuel leak; but did not shut down the engine because we agreed it was much more likely that the right fuel indicator was in error. We began monitoring fuel burn again from the new starting point to assure no leak. I did turn off the auto-throttles and ran the number one engine at higher thrust and fuel burn then the number two engine for the remainder of the flight in an attempt to rebalance the fuel. However; I did not open the crossfeed to rebalance until we could ensure no fuel leak. We landed with a fuel imbalance of approximately 3;600 LBS.
B737 Captain elected to return to the departure airport after the First Officer indicates the aircraft cannot be trimmed. A large fuel imbalance is noted; but suspected to be in error.