B747-400
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human-Machine Interface; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Diverted; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft; Equipment / Tooling
Aircraft had been written up several times for dual FMC failure en-route and subsequently had been signed off by Maintenance by resetting FMC circuit breakers and clearing any messages. We asked Maintenance this morning in ZZZ1 after the aircraft had been written up for dual FMC failure what their fix was going to be. Was told and I quote; 'Maintenance Control wants us to reset it and get this plane out on time.' None of us were happy with that statement; but given the message was cleared and both FMC's were working normally we decided to take the airplane. Departed ZZZ1 to ZZZ2 and all was fine; we programmed box to have entire route including a return into ZZZ1 in case of both FMC's failing we could navigate back to ZZZ1 with minimal input. Flight concluded without any anomalies. ZZZ2 to ZZZZ is a different story; around 26;000 feet we received an Auto-throttle Autopilot caution and dual FMC failure. We couldn't even finish checklist and both FMC's came back operational. Happened same thing 2 more times during climb and that's when we all decided that we were not crossing [ocean]; Class 2 navigation with intermittent FMC's. Contacted Dispatch via satellite communication; spoke with Dispatch; Duty Pilot and Chief Pilot to discuss our options and all came to same conclusion. ZZZ was our best option. We got at least 13 different times a FMC failure or dual FMC failure. We were able to fully complete checklist for DUAL FMC fail once; and the FMC's would eventually come back online. Ran all applicable checklists; backed up the arrival and connected the approach in the box to ensure if it failed for good we had ease of navigation. Had our flap speeds all figured out in case and had a good crew synergy working.Given our incident in ZZZ3; I'd suggest we no longer reset circuit breakers and get plane out on time as per Maintenance Control's quote from ZZZ1 this morning. This is not the first time this has happened; it was a multi-repeat item and a big ticket item as well. For future reference I will insist that the problem be addressed and looked at in greater detail before departing. The airplane has several 'repeat'/chronic issues that are being reset and sent on their way.
B747-400 flight crew reported dual FMC failure multiple times on the same flight.