What was found
AIRCRAFT WAS NOT GROUNDED, FLIGHT CREW REPORTED IN CRUISE AT FL330, ACFT LOST PRESSURIZATION. EMERGENCY DESCENT TO 10,000' WAS ACCOMPLISHED. PRESSURIZATION SYS STARTED WORKING AT 10,000 MSL P 4.3 V/SO CABIN ALT 400'. MAINTENANCE ACCOMPLISHED TSM 21-31-00-810-809-A, NO FAULT RECORDED ON PFR, PERFORMED CABIN PRESSURE SYS TEST IAW AMM 21-31-00-710-002-A, NO FAULTS NOTED.