Narrative:

We were cruising at FL330 and had requested FL350 for final due to gross weight; but after being held down at FL330 for a long time; we were now able to reach the flight planned cruise altitude of FL370. FL330 was in the MCP altitude window; autothrottles were on; VNAV path and FMC speed engaged; and FL350 was in FMC cruise altitude (planned cruise altitude due to weight). We notified ZAB we were now requesting FL370 as final altitude and I inserted that into the climb page of FMC. We immediately received the amber FMC light above the navigation display; the vtk amber box in lower right of navigation display and both fmcs and navigation display route blanked out. We were on the last leg of the cheez 2 RNAV departure; approaching dryht. I selected heading select on current heading. When we selected the legs page; the route came back up and we proceeded direct to dryht on LNAV. Not knowing if this was the cause or coincidence; I re-inserted FL370 in climb page of FMC and the same thing happened; only this time both fmcs and legs stayed blank. ATC cleared us to climb to FL370; which I did with autothrottles off and vertical speed of 1;000 FPM. The captain (pilot monitoring) informed ATC of our navigation loss and requested to proceed direct to cnx VOR; which we did with VOR/localizer capture. The captain then had to reinsert the route and all performance page information to regain FMC information for legs and climb N1 data; once level at FL370 all data was backed up properly so we re-engaged LNAV and autothrottles. We informed ATC that our navigation was functioning properly and we proceeded without further incident.

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Original NASA ASRS Text

Title: B737NG suffered two momentary losses of both FMSs and their associated navigational displays. Ultimately had to reload all route and performance data at which time the systems returned to normal.

Narrative: We were cruising at FL330 and had requested FL350 for final due to gross weight; but after being held down at FL330 for a long time; we were now able to reach the flight planned cruise altitude of FL370. FL330 was in the MCP altitude window; autothrottles were on; VNAV Path and FMC Speed Engaged; and FL350 was in FMC cruise altitude (planned cruise altitude due to weight). We notified ZAB we were now requesting FL370 as final altitude and I inserted that into the Climb Page of FMC. We immediately received the amber FMC light above the Navigation Display; the VTK amber box in lower right of Navigation Display and both FMCs and Navigation Display Route blanked out. We were on the last leg of the CHEEZ 2 RNAV Departure; approaching DRYHT. I selected Heading Select on current heading. When we selected the legs page; the route came back up and we proceeded direct to DRYHT on LNAV. Not knowing if this was the cause or coincidence; I re-inserted FL370 in Climb page of FMC and the same thing happened; only this time both FMCs and legs stayed blank. ATC cleared us to climb to FL370; which I did with autothrottles off and vertical speed of 1;000 FPM. The Captain (Pilot Monitoring) informed ATC of our navigation loss and requested to proceed direct to CNX VOR; which we did with VOR/LOC capture. The Captain then had to reinsert the route and all performance page information to regain FMC information for legs and Climb N1 data; once level at FL370 all data was backed up properly so we re-engaged LNAV and autothrottles. We informed ATC that our navigation was functioning properly and we proceeded without further incident.

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.