What was found
AT FL340 - AOA INDICATORS: CAPTAINS 2.0 FO'S 3.6 THE SPEED TAPE INDICATION ARE VERY CLOSELY MATCH TO ASA. GROUNDED - YES. AIR TURNBACK, FIM 34-21 TASK 834. SMYD BITE NO FAULTS. CAPT AOA REPLACED. FO AOA REPLACED. GVI GOOD. PERFORMED AOA SYS TEST IAW AMM 34-21-05. THE CAPT AOA WAS WITHIN LIMITS LEANS TOWARD -0.9. THE FO AOA WAS OUT OF LIMITS +1.3. REMOVED AND REPLACED THE FO SIDE (CH B) AOA IAW AMM 34-21-05. PERFORMED AOA SYS TEST. TEST GOOD. READINGS WERE ABOUT -0.4. C/W ADIRU LRU REPLACEMENT TEST REF FIM 27-11 TASK 802. ALL TESTS PASS.