What was found
IN-FLIGHT, AUTOPILOT B DISENGAGED, UNABLE TO REENGAGE. WAS ABLE AFTER 30 SECONDS TO ENGAGE A/P A. ACFT GROUNDED. ACCOMPLISHED DFCS BITE, IAW FIM 22-11 TASK 801. FLIGHT FAULT REVIEW SHOWED MESSAGES 22-11208 AND 22-11607 LOGGED ON BOTH FCC. ACCOMPLISHED STAB TRIM RELAY PROBLEM FAULT ISOLATION IAW FIM 22-13, TASK 818. MODE CONTROL PANEL PROBLEM FAULT ISOLATION IAW FIM 22-11, TASK 817. PERFORMED DFCS MCP LRU REPLACEMENT TEST IAW AMM 22-11-34/501. NO FAULTS FOUND. PRECAUTIONARILY REMOVED AND INSTALLED NEW R64 RELAY IAW WDM 22-13-11. ACCOMPLISHED REPAIR CONFIRMATION CHANNEL A AND B LIBRARY TEST SPEED/STAB TRIM 32. ALL TESTS PASSED.