Date: 202102
Local time of day: 0601-1200
Location: ZZZZ1.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZZ
ATC / advisory: Center ZZZZ1
Aircraft component: EICAS/EAD/ECAM
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Anomaly: Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Prior to departure Maintenance was called due to FOs (First Officer's) MAP failure on navigation display. Maintenance did a reset and signed off logbook as reset ok for service. FOs MAP was restored. Approximately 2 hours into flight and approximately 30 mins from ZZZZ1 enroute to ZZZZ; FOs MAP failed; followed by Captain's CWS (control wheel steering) fail; autothrottle failure; and SINGLE FMC operation message. Very shortly later; approximately 10 seconds; LNAV/ VNAV failed; both FMCs failed. Opposite autopilot selected; autopilot B. Captain's CWS was restored and one FMC was restored allowing for the engagement of LNAV/VNAV; and autothrottle was restored. FOs MAP still indicated a failure. Within approximately 60 seconds we had another dual FMC failure; followed by another LNAV/ VNAV failure; autothrottle failure; Captain's CWS failure. At this time with over two hours left to ZZZZ and navigating by raw data we decided it was the best course of action to divert to ZZZZ1 where the weather was favorable for landing with these navigational failures. We notified ZZZZ1 Center of our issues and intent to land in ZZZZ1. Around this time the Captain's FMC was restored automatically and we were once again able to navigate with LNAV/VNAV and the autothrottle and Captain's CWS was restored and autopilot was operational. As we neared ZZZZ1 we informed ATC of the need to hold to burn off fuel due to being overweight for landing which took approximately 10 minutes. The remainder of the flight was uneventful; we landed on Runway X and commenced the ILS approach in VFR conditions. The FOs MAP warning flag remained in view for the rest of the flight. My FO; Fas (Flight Attendants) did outstanding jobs. Great communication. ZZZZ1 ATC also very professional and helpful. In the 21 years I've been on the 737 both as an CA (Captain) and FO I've never experienced a dual FMC failure. I've experienced several single FMC failures; but not dual failures leading to several other navigation failures.




Synopsis: Captain reported a diversion to a precautionary landing following the loss of both Flight Management Computers which caused the loss of Cockpit Display Units and most navigation systems.