What was found
PRESSURIZATION SYSTEM LIGHT ON. CABIN ALTITUDE RATE GAUGE FLUCTUATING WILDLY. CABIN PRESSURE INDICATOR INOPERATIVE. TROUBLESHOT PRESSURIZATION SYSTEM IAW MM CHAPTER 21-30-00 PAGE 216 STEPS 1 THROUGH 25. FOUND NO DEFECTS WITH PRESSURIZATION CONTROLLING SYSTEM. OBSERVED CABIN PRESSURE INDICATOR FLUCTUATING FROM PLUS 2000 FEET TO -2000 FEET WITH ONLY APU OPERATING. INSTALLED SERVICEABLE CABIN PRESSURE INDICATOR AND PERFORMED SUCCESSFUL OPERATIONAL CHECK OF THE CABIN PRESSURIZATION SYSTEM IAW THE MM CHAPTER 21-30-00 PATE 201 STEP A. RETURNED AIRCRAFT TO SERVICE. (M)