What was found
L & R FMC FAIL. FOLLOWED QRH & FMCS DID NOT COME BACK. ATTEMPTED BITE OF LH AND RH FMC BOTH FMC COMPUTERS SHOW RED FAILURE LIGHT. IF WARN ELEX MESSAGE IS NOT DISPLAYED, VERIFY AND RECORD IN THE AML/EAML THAT THE WARN ELEX MESSAG E IS NOT ANNUNCIATED PRIOR TO EACH FLIGHT. IF WARN E LEX MESSAGE IS DISPLAYED, VERIFY AND RECORD IN AML/E AML THAT WEU POWER SUPPLIES OPERATE NORMALLY PRIOR T O EACH FLIGHT. UNABLE RNAV RNP AR APPROACHES HUD TAK EOFF GUIDANCE NOT AUTHORIZED NO ADS-B OUT OPERATIONS " LH AND RH FMC'S WERE REPLACED IN KHTS ON 02/17/2023.