A B737-800's fuel totalizer froze after becoming erratic in flight. The QRH instructed the crew to m...

Narrative:

Started to get various fuel messages on FMC. Fuel readings on EICAS showed left fuel reading erratic. Finally went blank. Fuel totalizer froze at last reading for some time. Followed QRH which states to update performance utilization page manually. This procedure does not work. You cannot update fuel on the performance utilization page. You cannot update fuel on page 1 of the program page. You can update your gross weight on the performance utilization page but this lowers or raises your ZFW making for inaccurate predictions. The only thing worth updating with a failed fuel reading is the utilization reference page for your approach speed. I checked this the rest of the aircraft I flew during my sequence. The MEL and the QRH both state to update the performance utilization page and are therefore misleading and wrong. The only thing you can do is select fuel used on the EICAS and check for excessive fuel flow/engine readings. This is totally inadequate as the FMC on the F-100/B-757/767/777 all allow for a 'manual' insertion of fuel on the performance utilization page which then updates your gross weight and fuel calculations appropriately. Fuel reading on left engine came back to life upon shutdown.

Original NASA ASRS Text

Title: A B737-800's Fuel Totalizer froze after becoming erratic in flight. The QRH instructed the crew to manually enter the fuel information in the FMC. However neither the FMC PERF INIT nor PROG pages could be updated manually.

Narrative: Started to get various fuel messages on FMC. Fuel readings on EICAS showed left fuel reading erratic. Finally went blank. Fuel totalizer froze at last reading for some time. Followed QRH which states to update performance utilization page manually. This procedure does not work. You cannot update fuel on the performance utilization page. You cannot update fuel on page 1 of the program page. You can update your gross weight on the performance utilization page but this lowers or raises your ZFW making for inaccurate predictions. The only thing worth updating with a failed fuel reading is the utilization reference page for your approach speed. I checked this the rest of the aircraft I flew during my sequence. the MEL and the QRH both state to update the performance utilization page and are therefore misleading and wrong. The only thing you can do is select fuel used on the EICAS and check for excessive fuel flow/engine readings. This is totally inadequate as the FMC on the F-100/B-757/767/777 all allow for a 'manual' insertion of fuel on the performance utilization page which then updates your gross weight and fuel calculations appropriately. Fuel reading on left engine came back to life upon shutdown.

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	865638
Time
Date	200912
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	Captain Pilot Flying
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Inflight Event / Encounter Fuel Issue

A B737-800's fuel totalizer froze after becoming erratic in flight. The QRH instructed the crew to manually enter the fuel information in the FMC. However neither the FMC perf init nor prog pages could be updated manually.