What was found
DURING INITIAL DESCENT AT ABOUT 1000 FPM, THE CABIN BEGAN A RAPID CLIMB OF OVER 1500 FPM. COM PROCEDURES WERE COMPLIED WITH BUT DID NOT HELP. WITH CABIN ALTITUDE CLIMBING ABOVE 10,000, CREW DONNED OXYGEN MASKS, DECLARED AN EMERGENCY, AND PERFORMED A RAPID DESCENT. ONCE AIRCRAFT WAS LEVEL AT 9000 FT AND ADDED POWER SETTINGS, THE CABIN PRESSURE RETURNED TO NORMAL CONTROL AND MADE A NORMAL DESCENT UNTIL LANDING. MAINTENANCE COULD NOT FIND ANY POSITIVE FAULT WITH THE SYSTEM AND REPLACED THE COALESCER BAGS.