As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A SCHEDULED INSPECTION, PREFORMED A PRODUCT IMPROVEMENT, REPLACEMENT OF DUCT ASSY 6914070-67. NOTICED THAT THE HEAT EXCHANGER SIDE PLATE HAD TWO CRACKS ABOUT .50 INCHES LONG AND ANOTHER .20 INCHES LONG. OPPOSITE SIDE OF THE HEAT EXCHANGER WAS CRACKED IN NONE OF THE FOUR CORNERS. A NEW HEAT EXCHANGER WAS INSTALLED. PERFORMED A LEAK CHECK ON THE DEFECTIVE UNIT AND FOUND THE CRACKS EXTENDED INTO THE COOLING FIN AREA, WHERE THEY CAN NOT BE SEEN.