As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN COMPLETING ANNUAL INSPECTION, CABIN HEATER ASSEMBLY WAS REMOVED FOR LEAK INSPECTION. FOUND ONE OF MUFF SUPPORT RINGS CRACKED HALF WAY AROUND. IF THIS WOULD HAVE CRACKED ALL THE WAY OFF THE EDGE WOULD HAVE CUT THROUGH EXHAUST PIPE PART OF MUFF, THIS WOULD LET CO INTO THE CABIN.