What was found
CREW REPORTED PRESSURIZATION CONTROL INEFFECTIVE, CABIN RATE CLIMBING AND DESCENDING, WHILE DESCENDING IN AUTOMATIC MODE. STABILIZED BRIEFLY WHILE IN MANUAL MODE. TROUBLESHOT IAW FIM 21-30-00, EXCESSIVE LEAK RATE NOTED AT TEST PORT 2. FOUND LOOSE (B) NUT ON CONTROL LINE TUBE ASSY. AT TEE FITTING FOR MANUAL CONTROL VALVE. CORRECTED LOOSE FITTING AND SYSTEM TESTS OK. RESTORED AC TO NORMAL CONFIGURATION, PRESSURIZATION SYSTEM TESTS SATISFACTORY ON GROUND RUN-UP. UNKNOWN IF PREVIOUS MAINTENANCE PERFORMED IN THIS AREA. (K)