B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 4029; Flight Crew Type 2255
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem; Flight Crew Landed As Precaution
Aircraft
At 35;000 FT; both the First Officer`s and Captain`s navigation displays went blank. The autopilot then disengaged. After about 30 seconds; we got the message single FMC operation. The captain`s navigation display came back on. We were unable to re-engage the autopilot. We attempted to complete the irregular checklist for FMC FAIL. It was determined that the right FMC had failed. The checklist has us go to POS SHIFT (Position Shift) page 3/3. We were unable to do so because both CDU`s were inoperative. We were unable to go to the POS Shift page. At that point; we decided the best course of action was to [return to our departure Airport]. We were still in VHF radio contact with [ATC]. We told them our intentions of returning to [the Airport] and asked for a vector. After turning back; we communicated with the Flight Attendants; passengers; and dispatch. Dispatch agreed that [our elected diversion Airport] was the best place to go. We decided to begin a descent early so that we might burn a little extra fuel so that we wouldn`t land overweight.After about 10 minutes the First Officer`s CDU began to work sporadically. The Captain`s CDU was still inoperative. Using the First Officer`s CDU we were able to program [the new destination]. After about 15 minutes; we were able to engage the left autopilot. The Captain`s CDU began to work during the final 10 minutes of the diversion. We were given vectors to land on runway XXL. It was a normal landing; [which] was under the maximum landing weight.
A Boeing 737 Captain reported that during cruise; both navigation displays went blank and the autopilot disengaged.