What was found
FLIGHT ATTNDANTS, PASSENGERS, AND FLIGHT CREW NOTICED A STRONG CABIN ODOR ENTIRE FLIGHT. STRONGEST ODOR DURING CLIMB AND DESCENT IN AFT CABIN. PERFORMED FIM TASK 21-20-00-810-801-A. WHILE RUNING #1 ENGINE ALREADY STARTED #2 ENGINE AFTER THE START VALV CLOSED GOT A FAINT SMELL WHEN THE PACKS TURNED ON. BOTH ENGINE BLEEDS ARE SHUTT OFF AT THIS TIME. SMELL WENT AWAY AFTER 15 SECONDS. MULTIPLE RECENT ODOR WRITE UPS ON THIS A/C. ODORS HAVE OCCURED IN FLIGHT AND ON GROUND UNDER APU AND BOTH ENGINE BLEEDS. INSPECTED BOTH PACK AIR CYCLE MACHINES. FOUND SIGNIFICANT CONTAMINATION IN NR 2 ACM. R & R NR 2 ACM IAW AMM 21-51-05. OP CHECKED GOOD. NO UNUSUAL ODORS DETECTED. ACFT OK FOR CONTINUED SERVICE.