What was found
CAPTAIN REPORTED THAT DURING DESCENT BOTH COMPASS OPENED, AUTO PILOT DEACTIVATED AND HEADING LIGHT AND AUTOMATIC ACCELERATORS SHUTDOWN. AHRU´S WERE CHECKED BY CONDITION AND LT AHRU WAS DETECTED WITHOUT SYNCHRONY AND OPENED MORE THAN 45 DEGREES. AHRU WAS INTERCHANGED AND TESTED CORRECT SO AIRCRAFT WAS DISPATCHED. LATER, CAPTAIN PERFORMED AN UNSCHEDULED LANDING AT GDL DUE TO RIGHT COMPASS FAILED DURING FLIGHT. DURING MAINTENANCE REVISION, AHRU NR 1 WAS DETECTED DAMAGED WITH BURNED ODOR IAW FAILURE OF ITS COOLING FAN. AHRU NR 1 WAS REPLACED IAW MM 34-21-10 AND 34-21-00, TESTED CORRECT.