What was found
(CAN) DID AN AIR TURNBACK DUE TO PROBLEMS WITH THE F/O NAVIGATION SYS. CREW REPORTED THAT THE TCAS FAIL ANNUNCIATED ON F/O NR 2 NAVIGATION DISPLAY, FOLLOWED BY LOSS OF HEADING DATA ON NR 2 PRIMARY FLIGHT DISPLAY, UPON LANDING LOSS OF ALL MAP DATA ON F/O NR 2 NAVIGATION DISPLAY ACCOMPANIED BY "MAP" FLAG ON F/O NR 2 NAVIGATION DISPLAY. ALSO F/O ROLL BAR NOT AVAILABLE ON NR 2 DISPLAY. DUE TO NO MAINTENANCE SUPPORT FLIGHT OPERATION OPTED TO RETURN FOR DEFECT RESOLUTION. MAINTENANCE TROUBLESHOOTING CARRIED OUT, BITE TEST CARRIED OUT IAW FIM 22-11, TASK 807. RT ADIRU FOUND AT FAULT UNIT REPLACED IAW AMM 34-21-01, FUNCTION TEST CARRIED OUT IAW AMM 34-21-00.