What was found
CABIN DIFFERENTIAL PRESSURE EXCEEDED. RECOMMENDED VALUES FOR ALTITUDES PER FM1.30.3, FELT ABNORMAL PRESSURE IN CLIMB & DECENT, BOTH PRESSURIZATION CONTROLLERS BITE TEST PASSED IAW AMM 21-31-00. NO FAULTS LATCHED. CREW VERBAL, PRESSURE CHANGE WAS NOTICEABLE. FLIGHT ORIGINALLY PLANNED FO FL 40000 BUT STOPPED CLIMB AT FL 30000 DUE TO DELTA P AT 8.4 PSI. PACK PRESSURE SPLIT WAS NEGLIGABLE. OUTFLOW VALVE WAS CLEAR. CREW DID NOT SELECT ALTERNATE OR MANUAL. CABIN RATE OF CLIMB WAS NORMAL. REF FIM 21-31 TASK 815 FAULT 30 WAS NOT FOUND ON EITHER DCPC 1 OR 2 SO DUE TO THIS ENGINE BLEED AIR SYS HEALTH CHECK MUST BE PERFORMED AND AIR CONDITIONING PACK AIR FLOW AND THE FUSELAGE LEAKAGE RATE AIRPLANE PACK OPERATION - CONFIDENCE CHECK CONTINUED WITH FIM 21-31 TASK 815 AT STEP F.2.A. PERFORMED ENGINE BLEED AIR SYSTEM HEALTH CHECKS FOR ENGINE 1 AND 2 REF AMM 36-11-00-700-801. FOUND NO ISSUES, LEAKS, OR ABNORMALITIES WITH EITHER ENGINE. CONTINUE WITH FIM 21-31 TASK 815 AT STEP F.2.B.-PERFORM THE FUSELAGE LEAKAGE RATE CHECK/ AIRPLANE PACK OPERATION CONFIDENCE CHECK, REF AMM 21-00-05-780-801 COMPLETED FIM TASK 21-31 TASK 815 STEP F (2) B & C. ALL CHECKS GOOD, NO DEFECTS NOTED. ADD EMP:U094459 REF LOG PG. 8095713. OUTFLOW VALVE REPLACED.