As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT#394, DEN-BOS. 'NOTICED SIMILAR ODOR AS DENVER PREVIOUS FLIGHT DESCENDING THROUGH 5500'. INFLIGHT REPORTED THE SMELL WAS STRONG IN THE CABIN; COMPLIED WITH INFO NOTICE 2017-T015, SECTION B2. IDENTIFIED ODOR AS OIL LEAK FROM APU COOLING FAN AND TRANSFER TUBE. REPLACED TORN O-RING & TRANSFER TUBE IAW AMM 49-52-51. DECON LEVEL C WAS ACCOMPLISHED PER TSM 05-50-00-810-831-A. ACFT IS OK FOR SVC.'