As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK DUE PILOT REPORT 4273256-1; EICAS MSG L FMC FAIL DISPLAYED. FIM 34-61-00 FOLLOWED L FMC PWR RESET ALL INDICATIONS NORMAL. PLS MONITOR FURTHER. AS A PREVENTIVE ACTION DURING OVERNIGHT; IAW AMM 34-61-01/401 WAS REMOVED AND REPLACED THE FLIGHT MANAGEMENT COMPUTER. (K)