B737 Next Generation Undifferentiated
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 208; Flight Crew Total 14976
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Overcame Equipment Problem; Flight Crew Returned To Clearance
Aircraft
At cruise; both FMCs failed with no annunciators except for momentary VTK annunciator on Captain's instruments. FMC prompt disappeared from both CDUs. A few seconds later; aircraft went into CWS for roll and auto throttles attempted to go to full idle. Crew began to execute checklist and troubleshoot the problem. Because aircraft went into CWS for roll; and heading select would not function; aircraft drifted slightly off course as crew analyzed the various failures. ATC noticed and asked us where we were going. I informed ATC of our failures. He gave us a heading to correct. Three minutes later all systems self-restored and we continued without further anomalies. Captain made a [logbook] entry. ATC was advised immediately of our restored systems and that we needed no further assistance. Captain was about to inform ATC of our system failure when ATC noticed our slight course deviation.
B737NG Captain reported a track error occurred following loss of both FMCs in cruise flight. A few minutes later; all systems returning to normal with no action taken by the crew.