What was found
CLT TO BNA HAD THE NR 2 PACK PRODUCE A BURNING SMELL WHILE IN USE. MAINTENANCE PLACED THE PACK ON MEL. AIRCRAFT DEPARTED WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED 3 DUCTS, OPS CHECKED GOOD. P/N 145-22273-401, 145-22277-403 AND 145-22285-401, ALL NON SEARILIZED.