What was found
AT FL200, AIRCRAFT LOST PRESSURIZATION. CABIN WENT TO 11,500 FEET. COM PROCEDURES ENABLED RECOVERY OF PRESSURE IN MANUAL MODE. INITIATED EMERGENCY DESCENT. FLIGHT ATTENDANT REPORTED SMOKE AND POSSIBLE FLAMES IN TAILCONE AREA. THERE WAS NO OTHER COCKPIT INDICATION TO SUPPORT FIRE CLAIM. AIRCRAFT LANDED SAFELY AT MEM. MAINTENANCE FOUND LOOSE DUCT OFF ACM IN TAIL AREA AND REINSTALL DUCT. AIRCRAFT RETURNED TO SERVICE.