Narrative:

The right center fuel pump had been deferred. After running the APU on the left center fuel pump; we noticed that the low pressure light was illuminated indicating a possible failure of the left center fuel pump. I notified maintenance; maintenance control; and flight control; and the decision was made to defer both center fuel pumps. We noticed that the center fuel tank contained 1;260 pounds (more than the 1;000 pound limit;) and voiced concerns about the legality of the deferral. Maintenance control posited that the 1;000 limit did not apply as the fuel in the wing tanks was 'scheduled' to be full. I agreed that we were starting out with full wing tanks; but that the fuel 'schedule' would leave us without full wing tanks; with more than 1;000 pounds in the center tank in apparent violation of the limitation - 'number main tanks 1 and 2 must be scheduled to be full if center tank contains more than 1;000 lbs of fuel.' the chief pilot was brought into the conversation; and he agreed with the interpretation of maintenance control. The salient question is what is the definition of 'scheduled;' and while I agreed at the time; upon further consideration; I am still uncertain about its meaning.the use of the term 'scheduled;' is confusing at best. Is the intention to allow a takeoff if the wing tanks are full at block out; or is the term 'scheduled;' meant to include the scheduled fuel burn?the limitation; and the [dispatch terminology]; should be clear about the intent and execution of the operation under these conditions.

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Original NASA ASRS Text

Title: B737 flight crew reported confusion when the term 'scheduled' was used in relation to the amount of fuel required with the center tank fuel pumps being placed on MEL.

Narrative: The right center fuel pump had been deferred. After running the APU on the left center fuel pump; we noticed that the low pressure light was illuminated indicating a possible failure of the left center fuel pump. I notified maintenance; maintenance control; and flight control; and the decision was made to defer both center fuel pumps. We noticed that the center fuel tank contained 1;260 pounds (more than the 1;000 pound limit;) and voiced concerns about the legality of the deferral. Maintenance Control posited that the 1;000 limit did not apply as the fuel in the wing tanks was 'scheduled' to be full. I agreed that we were starting out with full wing tanks; but that the fuel 'schedule' would leave us without full wing tanks; with more than 1;000 pounds in the center tank in apparent violation of the limitation - 'Number Main tanks 1 and 2 must be scheduled to be full if center tank contains more than 1;000 lbs of fuel.' The Chief Pilot was brought into the conversation; and he agreed with the interpretation of Maintenance Control. The salient question is what is the definition of 'scheduled;' and while I agreed at the time; upon further consideration; I am still uncertain about its meaning.The use of the term 'scheduled;' is confusing at best. Is the intention to allow a takeoff if the wing tanks are full at block out; or is the term 'scheduled;' meant to include the scheduled fuel burn?The limitation; and the [dispatch terminology]; should be clear about the intent and execution of the operation under these conditions.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.