Narrative:

Enroute at FL410; the center fuel gauge started increasing and indicated a max of 29;440. FMC showed increase (could not manually update). Speed tapes and MCP speed indications all had maxed out readings. Autothrottles did not seem to have control of thrust. QRH was looked at but did not directly address this issue and known information on inop fuel gauge updates per performance data and FMC as well as test FMC to accept updated ldg weight (worked). Maintenance control; dispatch; and chief were consulted. The concern was indications on approach/landing and possible stick shaker activation. Center fuel was assumed empty by estimating 2;000 pounds and complying with fuel pump/crossfeed requirements until fuel pump low pressure light indicated depletion. Main gauges operated normally. With company's concurrence; we elected to update ldg weight and attempt approach/land in our filed destination with known ldg weight; fuel; and company calculated numbers. Brief included manually setting speed bugs (if needed); stick shaker activation and landing/go around per company's/crew input. Center fuel decreased to 28;000 and remained there throughout the descent and landing. The approach and landing were normal as well as indications of tapes; speeds; bugs and MCP indications. Normal gate arrival and deplane. Center fuel at shut down 24;550.

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Original NASA ASRS Text

Title: At cruise; a B737-700 FMC center fuel tank indicated 29;440; the speed tapes; MCP speed indications all had maxed out readings and the autothrottles did not seem to have control of thrust. All indications except Center Fuel Tank quantity returned to normal during descent. A loose cannon plug was implicated.

Narrative: Enroute at FL410; the center fuel gauge started increasing and indicated a max of 29;440. FMC showed increase (could not manually update). Speed tapes and MCP speed indications all had maxed out readings. Autothrottles did not seem to have control of thrust. QRH was looked at but did not directly address this issue and known information on inop fuel gauge updates per performance data and FMC as well as test FMC to accept updated LDG WT (worked). Maintenance Control; Dispatch; and Chief were consulted. The concern was indications on approach/landing and possible stick shaker activation. Center fuel was assumed empty by estimating 2;000 LBS and complying with fuel pump/crossfeed requirements until Fuel Pump Low Pressure light indicated depletion. Main gauges operated normally. With Company's concurrence; we elected to update LDG WT and attempt approach/land in our filed destination with known LDG WT; fuel; and Company calculated numbers. Brief included manually setting speed bugs (if needed); stick shaker activation and landing/go around per Company's/crew input. Center fuel decreased to 28;000 and remained there throughout the descent and landing. The approach and landing were normal as well as indications of tapes; speeds; bugs and MCP indications. Normal gate arrival and deplane. Center fuel at shut down 24;550.

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.