Date: 201907
Local time of day: 0601-1200
Location: SFO.Airport, CA
Flight conditions: VMC
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Fuel Quantity-Pressure Indication
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Training / Qualification; Time Pressure; Communication Breakdown
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural MEL / CDL
Detector: Person Flight Crew
When detected: Pre-flight
Result: General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Procedure; Manuals; MEL
Primary problem: Procedure

Narrative: Upon reviewing the [deferred items list] during preflight preparation I noticed an inoperative right main tank gauge; flight deck and fueling panel; and fuel totalizer. When I walked onto the flight deck there were two mechanics that were discussing the fuel system/load and were communicating with someone outside of the aircraft. I walked in mid conversation and was only catching one side of the conversation. My take was that there were some communication issues taking place between the mechanics and whomever they were speaking with. One Mechanic kept stating 'There is 7.5 on board'. The left main tank showed 7.5 while the right tank (inoperative) and total (inoperative) were blank. Stating '7.5 on boar' was not an accurate description on the fuel state of the aircraft; only the quantity of the left main tank. As the mechanics were leaving I commented that it appeared that they were having communication issues. I believe that this description of '7.5 onboard' contributed to the first error of overfilling the right main tank. After seeing this poor communication and ambiguity; I spoke; in person; to a Maintenance Supervisor on the ramp and requested the specific drip stick quantity of the right tank. He said that it would be provided. We received our [flight data] 3 minutes before scheduled departure time and it showed a slightly over fueled right main tank and an imbalance of 600lbs which is within limits. I had the understanding that this was the provided tank quantity from maintenance from a drip stick check of 8100lbs in the right (inoperative gauge) tank.We received a new [maintenance release] post fueling as required by the MEL. After being told that ramp was ready for push; another voice came over the inter phone and stated that the actual fuel quantity of the right tank was 8700lbs (full) and that we had an out of balance condition between right and left tanks in excess of 1000lbs. The Maintenance Personnel over the inter phone requested our assistance in transferring fuel between tanks to balance the fuel within limits. Due to the many errors that had already taken place; and the likely event of future errors transferring fuel out of a tank with an inoperative gauge; I requested a fuel truck to bring the left tank quantity up to match the over fueled right tank. I requested a new release from Dispatch due to the increased weight. There were two significant errors that took place with the higher threat MEL of an inoperative fuel gauge. The first error is that we were mis fueled. The second error was that we received an inaccurate [flight data] that did not reflect the actual fuel load of the aircraft. What was done properly was the Maintenance individual who recognized the fuel slip error vs actual load and imbalance and spoke up to prevent us from departing before fixing the out of balance condition. The apparent miscommunication that took place early on in the fueling process combined with the two errors gives me the impression that those involved were not following a set fueling SOP for an inoperative gauge and/or were not adequately trained.




Synopsis: B737 Captain reported confusion during fueling with inoperative fuel quantity gauges; resulting in a fuel imbalance and delay for correction.