As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKEOFF, ON CLIMB-OUT, THE FLIGHT CREW RECEIVED A NR 1 STRUT OVERHEAT INDICATION. THE ACFT RETURNED TO THE DEPARTURE AIRPORT FOR AN UNEVENTFUL, UNSCHEDULED LANDING. UPON INSPECTION BY MAINTENANCE, A DUCT LEAK WAS FOUND AT THE NR 1 ENGINE STRUT HEAT EXCHANGER. WHEN ATTEMPTING TO TIGHTEN THE COUPLING THE COUPLING BROKE. A NEW COUPLING WAS INSTALLED AND THE ACFT WAS RETURNED TO SERVICE.