What was found
PDIS 731, 34-63, 3866, 03SEP20, MEM FACT U. AT FL340 ADC 1 FAILED. AP 1 DISENGAGED, LOST PFD INSTRUMENTATION, ND UNAVAILABLE, FMC 1 FAILURE, ATS 2 TRIPPED OFF. RESET ATS 2 PER ECAM. COMPLIED WITH QRH FOR FMC UNAVAILABLE AND ADC INSTRUMENTATION FAILURE. AP2 INITIALLY COMMANDED A DIVE, DISCONNECTED. SUCCESSFULLY ENGAGED AP2 AFTER 5 MIN. DEPARTED RVSM AIRSPACE. DECLARED EMERGENCY. FACT 03SEP20 19:30 MEM U. PER CREW DEBRIEF NO ADC/NAV ECAM FAULTS, AND VALID A/S AND ALT SHOWN IN CREW PHOTO JUST AFTER FAULT BUT, DID HAVE SPEED LIMIT FLAG AND FD1 FLAG. FMS UNAVAILABLE DISPLAYED ON MCDU NR 1 AND NR 1 FMC FAILED ON MTP. COULD NOT GET FMC NR 1 TO RESET. REMOVED AND REPLACED NR 1 FMC IAW A300 AMM 34_68_34_04. OP CHECKS GOOD. NEW FMC HAD CURRENT NAV DATA BASE INSTALLED. REMOVED AND REPLACED NR 1 MCDU IAW A300 34_68_11_04. OP CHECKS GOOD. REMOVED AND REPLACED NR 1 ADC IAW A300 AMM 34_11_34_04. OP CHECKS GOOD. PERFORMED AFS LAND TEST IAW A300 AMM 22-40-00-5. ALL TEST PASSED.