What was found
CLT - WHILE ACCOMPLISHING A B-CHECK MAINTENANCE VISIT AN AREA OF DISCOLORATION ON THE CARGO LOADING JACKSCREW PAN OF THE AFT CARGO COMPARTMENT APPROXIMATELY 12-18 INCHES AFT OF THE FORWARD CARGO BULKHEAD WAS NOTED. FURTHER INVESTIGATION FOUND EVIDENCE OF A FIRE BELOW THE AFT CARGO COMPARTMENT FLOOR. THE IGNITION SOURCE OF THE FIRE APPEARS TO HAVE BEEN THE HEATER NUT ON THE HEATER FOR THE C-LAV FILL LINE. THE FAILED HEATER NUT APPEARS TO HAVE IGNITED THE ADJACENT FUSELAGE SKIN INSULATION BLANKETS SURROUNDING THE AFT LAVATORY SERVICE PANEL. MAINTENANCE REPAIRED ALL DAMAGED AREAS. THIS SYSTEM WILL BE DEACTIVATED ON ALL OF US AIRWAYS APPLICABLE AIRCRAFT. (M)