Narrative:

After takeoff on flight from sjc to nrt we experienced the loss of the #1 FMC. All operating manuals and company maintenance were consulted. It was agreed by all parties both airborne and on the ground that this loss would have no effect on the transpacific crossing and that all navigation equipment would work normally. The flight was uneventful and upon arrival nrt maintenance met the flight and debriefed the crew. The captain was told to enter the failure of an FMS in the logbook. The actual failure that had occurred was of an FMC. Prior to our next trip the captain was able to locate in our operating manual part 1 under normal procedures, preface, page 4, a note that with a loss of one FMS prior to oceanic entry the crew should divert to a suitable airport. Nothing could be found in the emergency section, conditionals section, or MEL concerning this FMC loss. A system loss which would require a diversion should be noted in the emergency section of the manual. It should be emphasized in training, maintenance and dispatch should be aware of its presence.

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Original NASA ASRS Text

Title: #1 FMC FAILED ON WDB EARLY IN CRUISE OF OVER OCEAN FLT. CONCURRENCE WITH GND PERSONNEL FLT CONTINUED TO DEST.

Narrative: AFTER TKOF ON FLT FROM SJC TO NRT WE EXPERIENCED THE LOSS OF THE #1 FMC. ALL OPERATING MANUALS AND COMPANY MAINT WERE CONSULTED. IT WAS AGREED BY ALL PARTIES BOTH AIRBORNE AND ON THE GND THAT THIS LOSS WOULD HAVE NO EFFECT ON THE TRANSPACIFIC XING AND THAT ALL NAV EQUIP WOULD WORK NORMALLY. THE FLT WAS UNEVENTFUL AND UPON ARR NRT MAINT MET THE FLT AND DEBRIEFED THE CREW. THE CAPT WAS TOLD TO ENTER THE FAILURE OF AN FMS IN THE LOGBOOK. THE ACTUAL FAILURE THAT HAD OCCURRED WAS OF AN FMC. PRIOR TO OUR NEXT TRIP THE CAPT WAS ABLE TO LOCATE IN OUR OPERATING MANUAL PART 1 UNDER NORMAL PROCS, PREFACE, PAGE 4, A NOTE THAT WITH A LOSS OF ONE FMS PRIOR TO OCEANIC ENTRY THE CREW SHOULD DIVERT TO A SUITABLE ARPT. NOTHING COULD BE FOUND IN THE EMER SECTION, CONDITIONALS SECTION, OR MEL CONCERNING THIS FMC LOSS. A SYS LOSS WHICH WOULD REQUIRE A DIVERSION SHOULD BE NOTED IN THE EMER SECTION OF THE MANUAL. IT SHOULD BE EMPHASIZED IN TRAINING, MAINT AND DISPATCH SHOULD BE AWARE OF ITS PRESENCE.

Data retrieved from NASA's ASRS site as of July 2007 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.