What was found
MRY/PHX - FLT 6088 - DURING FLIGHT, HAD THE A/P TRIM AND A/P TRIM ANNUNCIATOR ILLUMINATE. THE STABILIZER WAS STUCK AT MINUS 5 DEGREES NOSE DOWN. A/P DISCONNECTED AND TRIM STILL STUCK AT MINUS 5 DEGREES. EMERGENCY DECLARED AND AIRCRAFT LANDED WITHOUT INCIDENT AT FAT. MAINTENANCE REMOVED AND REPLACED THE STABILATOR TRIM ACTUATOR AND MOTOR CONTROL UNIT. AIRCRAFT TEST FLOWN, TEST FLIGHT GOOD. AIRCRAFT RETURNED TO SERVICE. (X)