As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHORTLY AFTER TAKEOFF, BOTH LEFT AND RIGHT FLIGHT MANAGEMENT COMPUTERS LOCKED UP AND WERE INOPERATIVE. CREW WAS DIRECTED MY MAINTENANCE CONTROL TO ATTEMPT CIRCUIT BREAKER RESET. THE AIRCRAFT RETURNED TO DEPARTURE AND LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS GROUNDED. REPLACED THE NR 2 FLIGHT MANAGEMENT COMPUTER IAW AMM 34-61-01.