As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TAIL COMPARTMENT HI TEMP LIGHT ILLUMINATED IN FLIGHT CLIMB 18,000. FOLLOWED EMERGENCY PROCEDURES AND ISOLATED THE RIGHT SYSTEM. THE LIGHT EXTINGUISH. AIRCRAFT AIR RETURNED. FOUND LOOSE DUCT ON RT PACK SUPPLY, RE-SECURED DUCT IAW MM 21-00 AND 36-00. OPS CHECKED GOOD.