What was found
CAPTAIN REPORTED THE PRESSURIZATION VERY UNSTABLE, NOT POSSIBLE TO PRESSURIZE AIR CONDITIONING PACKAGES. THE CABIN PRESSURE CONTROL WAS RESEATED IAW MM 21-32-04. LATER, AIRCRAFT RETURNED TO PLATFORM, PNEUMATIC LEAK ON RT AIR CONDITIONING. THE RUBBER HOSE BETWEEN HEAT EXCHANGER AND REFRIGERATION UNIT CLAMP WERE REPLACED IAW MM 21-20-00, TESTED CORRECT. DURING RT ENGINE START, THE IGNITION WAS OUT OF SERVICE. THE EXCITER IGNITION BOX WAS REPLACED IAW MM 74-1001, TESTED CORRECT. DURING OVERNIGHT CHECK, BOTH A/C REGULATION VALVES, LT A/C PILOT PRESS REGULATOR AND DUAL ACCELEROMETER WERE REPLACED IAW MM 21-31-01, MM 21-31-00 AND MM 22-219-02 RESPECTIVELY, TESTED CORRECT.