A B737-800 flight crew encountered a fuel imbalance warning that they were unable to correct due to ...

Narrative:

Misunderstood master caution logic of one center tank on and one off. Got distracted and left fuel crossfeed open with all main tank pumps and one center tank pump on. First officer noted low pressure light illuminated prior to fuel imbalance limitation (1;000 pounds). Captain configured for fuel re-balance but fuel continued out of same tank for short period; long enough to activate fuel imbalance alert. Fuel actually noted by first officer was exactly 1;000 pounds different (7.42 left and 8.42 right) but suspect actually exceeded due to alert activation.extensive search in the on-board documents; as well as all documents contained on the cockpit tablet computer; resulted in no less confusion on the exact logic or procedure for -800 jets versus -700/900 (certainly may exist but neither pilot could find the reference). All this plus the interruption that occurred when flight attendants passed meals forward caused the loss of concentration and subsequent imbalance.

Original NASA ASRS Text

Title: A B737-800 flight crew encountered a fuel imbalance warning that they were unable to correct due to confusion over the procedure logic regarding the 800 vice other NG models. Distractions with flight attendants delivering flight crew meals contributed to the failure to monitor the fuel issue.

Narrative: Misunderstood master caution logic of one center tank on and one off. Got distracted and left fuel crossfeed open with all main tank pumps and one center tank pump on. First Officer noted low pressure light illuminated prior to fuel imbalance limitation (1;000 LBS). Captain configured for fuel re-balance but fuel continued out of same tank for short period; long enough to activate fuel imbalance alert. Fuel actually noted by First Officer was exactly 1;000 LBS different (7.42 left and 8.42 right) but suspect actually exceeded due to alert activation.Extensive search in the on-board documents; as well as all documents contained on the cockpit tablet computer; resulted in no less confusion on the exact logic or procedure for -800 jets versus -700/900 (certainly may exist but neither pilot could find the reference). All this plus the interruption that occurred when flight attendants passed meals forward caused the loss of concentration and subsequent imbalance.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	958796
Time
Date	201107
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Fuel Distribution System
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Inflight Event / Encounter Fuel Issue

A B737-800 flight crew encountered a fuel imbalance warning that they were unable to correct due to confusion over the procedure logic regarding the 800 vice other ng models. Distractions with flight attendants delivering flight crew meals contributed to the failure to monitor the fuel issue.