What was found
ON TAKEOFF CABIN PRESSURIZATION WAS CLIMBING WITH THE AIRCRAFT. CABIN ALTITUDE MATCHED ALTIMETER AND VERTICAL SPEED INDICATOR AS WE CLIMBED TO 4000 FT. LOUD NOISE WAS HEARD ON MAIN CABIN DOOR INFLIGHT AT 200 KTS. PERFORMED OPS TEST OF THE PRESSURIZATION SYSTEM IN AUTOMATIC AND MANUAL MODE. OPS CHECKS GOOD REF. AMM 21-31-00. PERFORMED OPERATIONAL TEST OF THE PASSENGER DOOR SEAL REF. AMM 52-11-28. OPS AND LEAK CHECKS GOOD. SEALED LOWER HALF OF PASSENGER DOOR SEAL REF. AMM 52-11-28.