What was found
AIRCRAFT HAS EXPERIENCED 3 DIFFERENT AUTOPILOT PITCH TRIM PROBLEMS AT AIRCRAFT TOTAL TIMES OF 164.1 HOURS, 311.7 HOURS, AND 886.3 HOURS. SAMPLE PROBLEMS ARE 'TRIM HORN BEEPS ON A/P ENGAGEMENT' OR 'A/P PITCH TRIM FAIL LIGHTS INTERMITTENTLY'. TRIM SPEED ALSO SLOWS UP BEFORE FAILURE. ALL PROBLEMS WERE TRACED TO GROUP OF 3 RELAYS IN TRIM RELAY BANK. THESE ARE 3 OF 4 FAILURES IN 2 A/C FLEET.