Narrative:

The center tank fuel quantity indicator was written up for showing -500 pounds when the tank was empty; thus making the FMC read 500 pounds low. Maintenance decided to defer the gauge under MEL 28-23. Confusion ensued when one of the provisos called for deactivating the FMC fuel totalizer (fuel summation unit). There are apparently two separate ways to deactivate the totalizer depending on the aircraft tail number. Maintenance initially used the incorrect procedure. Maintenance control corrected the line mechanics and the proper procedure was then applied to the aircraft. There was then a discussion between myself and maintenance as to what exactly was being deferred and/or disabled. While maintenance was working on the logbook in the jetway; I called my dispatcher and amended the release to show the two deferrals that needed to be recorded. These were 28-7 center tank fuel quantity indicator and 28-23 fuel summation unit. With the logbook signed off and the release amended; we pushed back from the gate about 13 minutes late. During the pushback I noticed that I couldn't find any documentation showing that MEL 28-23 had been complied with except my amended release. We had the engines started and elected to release the ground crew and call maintenance and let them know that I now believed that there was some unfinished paperwork that needed to be completed. They told me to standby while they conferred with maintenance control. Simultaneously; I contacted my dispatcher to let him know what was happening. Maintenance control came back and said we didn't need a logbook entry for 28-23 as it was assumed to be inop under 28-7. My dispatcher asked if there was any documentation noting an inoperative summation unit. There was not; and so we decided to taxi back into the gate and get this mess sorted out. At the gate; myself (first officer) and the line mechanic re-read MEL 28-7 and it did seem like MEL 28-23 should be documented somewhere in the logbook after looking at proviso 'D' in MEL 28-7. Upon further review and discussions with my dispatcher and maintenance control; it was agreed on that proviso 'east' indicated that the fuel summation unit was assumed to be deactivated and a sticker noting MEL 28-23 affixed to a lower panel in the cockpit; along with a notation on the dispatch release was sufficient. I initially had a hard time accepting that one could have a sticker in the cockpit; but no associated documentation on either the inside cover of the logbook; or a log page write-up. After re-reading the MEL (which is still very poorly worded in my opinion) multiple times; I too was convinced that we were now legal to depart with only a MEL 28-23 sticker affixed next to the MEL 28-7 sticker. We pushed back for a second time and continued. Being a little behind schedule (prior to the first push) and given that fact that myself and the line mechanic had extensive conversations about what was being deferred; and the fact I notated the two mels on the release; when maintenance came back with the logbook; I failed to thoroughly review it before pushing. I assumed all was well. Clearly; the MEL can be difficult to interpret in the best of conditions. In the 'heat of the battle' it can be exceedingly difficult to understand. I would like to see a 'plain english' version or side notes added. For example: 'please note: MEL 28-23 need not be documented in the logbook; as it is covered in the aforementioned proviso.'

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Original NASA ASRS Text

Title: During pushback; a B737-300 Captain noticed he couldn't find any documentation showing that MEL 28-23 had been complied with for the deferral of the Center Tank Fuel Quantity indicator. Center Tank indicator was written-up showing -500 pounds low when tank was empty; thus making the FMC read 500 pounds low.

Narrative: The Center Tank Fuel Quantity indicator was written up for showing -500 LBS when the tank was empty; thus making the FMC read 500 LBS low. Maintenance decided to defer the gauge under MEL 28-23. Confusion ensued when one of the provisos called for deactivating the FMC Fuel Totalizer (Fuel Summation Unit). There are apparently two separate ways to deactivate the Totalizer depending on the aircraft tail number. Maintenance initially used the incorrect procedure. Maintenance Control corrected the Line Mechanics and the proper procedure was then applied to the aircraft. There was then a discussion between myself and Maintenance as to what exactly was being deferred and/or disabled. While Maintenance was working on the Logbook in the Jetway; I called my Dispatcher and amended the Release to show the two deferrals that needed to be recorded. These were 28-7 Center Tank Fuel Quantity Indicator and 28-23 Fuel Summation Unit. With the Logbook signed off and the Release amended; we pushed back from the gate about 13 minutes late. During the pushback I noticed that I couldn't find any documentation showing that MEL 28-23 had been complied with except my amended Release. We had the engines started and elected to release the Ground Crew and call Maintenance and let them know that I now believed that there was some unfinished paperwork that needed to be completed. They told me to standby while they conferred with Maintenance Control. Simultaneously; I contacted my Dispatcher to let him know what was happening. Maintenance Control came back and said we didn't need a Logbook entry for 28-23 as it was assumed to be Inop under 28-7. My Dispatcher asked if there was any documentation noting an inoperative Summation Unit. There was not; and so we decided to taxi back into the gate and get this mess sorted out. At the gate; myself (First Officer) and the Line Mechanic re-read MEL 28-7 and it did seem like MEL 28-23 should be documented somewhere in the Logbook after looking at Proviso 'D' in MEL 28-7. Upon further review and discussions with my Dispatcher and Maintenance Control; it was agreed on that proviso 'E' indicated that the Fuel Summation Unit was assumed to be deactivated and a sticker noting MEL 28-23 affixed to a lower panel in the cockpit; along with a notation on the Dispatch Release was sufficient. I initially had a hard time accepting that one could have a sticker in the cockpit; but no associated documentation on either the inside cover of the Logbook; or a Log page Write-up. After re-reading the MEL (which is still very poorly worded in my opinion) multiple times; I too was convinced that we were now legal to depart with only a MEL 28-23 sticker affixed next to the MEL 28-7 sticker. We pushed back for a second time and continued. Being a little behind schedule (prior to the first push) and given that fact that myself and the Line Mechanic had extensive conversations about what was being deferred; and the fact I notated the two MELs on the Release; when Maintenance came back with the Logbook; I failed to thoroughly review it before pushing. I assumed all was well. Clearly; the MEL can be difficult to interpret in the best of conditions. In the 'heat of the battle' it can be exceedingly difficult to understand. I would like to see a 'plain English' version or side notes added. For example: 'Please note: MEL 28-23 need not be documented in the Logbook; as it is covered in the aforementioned proviso.'

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.