At 2115 eastern time, a Piper PA-23-250 was substantially damaged by fire at the Buffalo Niagara International Airport. The pilot was not injured. The Part 135 cargo flight had originated at Morristown, N.J., and was taxiing to the ramp at Buffalo after landing when the pilot noticed a burning smell in the cockpit, and then an orange glow at his feet. An FAA inspector found that the fire had burned a hole through the fuselage skin near the Janitrol heater. The entire area forward of the Janitrol heater, including the instrument panel, was consumed by fire. The pilot stated that his normal procedure for using the Janitrol heater was to turn it off at the same time he extended the landing gear while on approach, and that he had followed this procedure on this flight.