As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHL - FLT1227, EN ROUTE FROM BTV TO PHL, CREW REPORTED A STRONG OIL SMELL IN CABIN. CREW WAS ABLE TO ISOLATE SOURCE TO LEFT PACK/LEFT ENGINE. FLIGHT LANDED AT PHL WITHOUT FURTHER INCIDENT. MAINTENANCE ACCOMPLISHED FAULT ISOLATION STEPS FROM MM 21-00-01, PROCEDURE 2. NO FAULTS CONFIRMED. NO UNUSUAL ODORS OR FUMES NOTED WHEN OPERATING LEFT PACK FROM LT ENGINE. AIRCRAFT OK FOR SERVICE.