What was found
UPON DESCENT FROM FL290 TO FL270, THE CABIN PRESSURE LIGHT AND THE MASTER WARNING LIGHT ILLUMINATED. CREW INITIATED AN EMERGENCY DESCENT AND DONNED OXYGEN MASKS. ALL CABIN OXYGEN MASKS DEPLOYED. THE AIRCRAFT LEVELED OFF AT 10,000 FEET AND CONTINUED TO DFW. MAINTENANCE INSPECTED ALL DUCTS IN THE TAIL COMPONENT BUT NO LEAKS WERE FOUND. ALL DOOR SEALS WERE CHECKED AND THE AIRCRAFT WAS PRESSURIZED TO 2.9 PSI. NO LEAKS WERE FOUND. AIRCRAFT RETURNED TO SERVICE.