As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GYR - AFTER TAKEOFF APU FIRE DETECTION FAULT LIGHTS ON FIRE WARNING PANEL ILLUMINATED. AIRCRAFT RETURNED TO GYR AND LANDED WITHOUT INCIDENT AND NO EMERGENCY WAS DECLARED. REPLACED FIRE DETECTION ELECTRONICS RACK MODULE. OPERATIONS CHECKED GOOD. (M)