What was found
(CAN) THE FLIGHT CREW REPORTED THAT DURING THE OFF-LOADING OF BAGGAGE, IT WAS NOTICED THAT THE RT SIDE WALL OF THE BAGGAGE COMPARTMENT WAS VERY HOT. A PLASTIC BAG WHICH HAD BEEN IN CONTACT WITH THE SIDE WALL HAD MELTED. AN INVESTIGATION WAS CARRIED OUT, RT HEATER PANEL PN 3436-05-1/0 (ITEM NOT SERIALIZED) WAS FOUND TO BE INOPERATIVE AND THE PANEL WAS FOUND TO HAVE A VISIBLE TRACE OF OVERHEATING . IT IS SUSPECTED THAT THE THERMAL SWITCH FAILED, THEREBY ALLOWING THE TEMPERATURE OF THE HEATER ELEMENT TO INCREASE TO A HIGH HEAT LEVEL. SUBSEQUENTLY, THE THEORY IS THAT HEATER ELEMENT FAILED PROBABLY DUE TO THE INCREASE IN TEMPERATURE.