What was found
ABOUT 30 MINUTES AFTER FIRST OFFICERS EADI FAILED, PIT YELLOW FLAG ON CAPTAIN AND FIRST OFFICERS AND A/P STARTED PITCHING UP AND HAD TO BE DISCONNECTED. FIVE MINUTES LATER, HDG YELLOW FLAG AND WE HAD 10 FT-15 FT DIFFERENCE FROM CAPTAINS TO FIRST OFFICER'S HEADING INDICATORS. DIVERTED FROM SFO TO FAT. REPLACED FIRST OFFICER'S AHRS COMPUTER. FIRST OFFICER'S AND CAPTAIN'S AHRS SYSTEM TESTS NORMALLY PER MM 34-21-00. BOTH A/P AND FD SYSTEMS TEST NORMALLY PER MM 22-11-00.