As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HEATER WAS NOTICED TO BE WEAK IN FLIGHT. ENGINEER FOUND THE HEATER NOZZLE HOSE UNDER THE CABIN FLOOR TO BE COMPLETELY DETERIORATED. LOOKED LIKE GLUE LET GO AND THE INSULATION WAS BLOWN EVERYWHERE. PART WAS REPLACED WITH NEW AND MANUFACTURER WAS INFORMED.