What was found
DURING A MAINTENANCE ACCEPTANCE FLIGHT, SOMETIME AFTER INITIATING CABIN HEAT, IT WAS NOTICED THAT THE FLIGHT STATION WAS BECOMING HAZY. THE PILOT LOOKED AFT AND SAW THAT THE CABIN WAS ALSO HAZY. CABIN HEAT WAS SECURED, AND THE AIRCRAFT VENTILATED. SUBSEQUENT GROUND INVESTIGATION REVEALED AN INSULATION BLANKET IN CONTACT WITH THE CABIN BLEED AIR TUBE. INSULATION BLANKETS WERE RESECURED AND RESTORED TO ORIGINAL CONFIGURATION. PERFORMED CHECKS AND OPERATION OF CABIN HEAT WITH NO DEFECTS NOTED.