What was found
ODOR IN COCKPIT & CABIN NOTICED BY CREW AND PASSENGERS. UNABLE TO DETERMINE WHETHER ENVIRONMENTAL OR ELECTRICAL. ODOR SLOWLY DISSIPATED DURING DESCENT. VERIFIED COCKPIT FILLS WITH SMOKE WITH ACM OPERATION. ACCOMPLISHED TROUBLESHOOTING PROCEDURES FOR AN ODOR OF OIL OR SMOKE IN THE CABIN OR COCKPIT PER MM 21-52-00. SOURCE OF SMOKE DETERMINED TO COME FROM COCKPIT ACM. REMOVED AND REPLACED AFT ACM IAW MM 21-51-00. SERVICED UNIT WITH OIL IAW MM 12-10-01. OPS & LEAK CHECKED GOOD.