What was found
AIRCRAFT PERFORMED AN UNSCHEDULED LANDING AS A CONSEQUENCE OF PROBLEMS WITH THE STABILIZATOR. CAPTAIN REPORTED THAT DURING CLIMB THE LIGHT OF -AP TRIM- TURNED ON. ABNORMAL PROCEDURE WAS ACCOMPLISHED, THE CIRCUIT BREAKERS D9, D10 AND D11 WERE RESEATED BUT THEY OPENED AGAIN. DURING MAINTENANCE ACTIVITIES THE SWITCH S10-21 WAS FOUND DAMAGED. THE SWITCH WAS REPLACED IAW M/M 20-50-00 AND RTS SYSTEM WAS TESTED IAW M/M 22-01-05, BEING ALL CORRECT.