As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHL FLT 1037 EN-ROUTE PHL TO SJU. A BURNING, OIL ODOR WAS NOTED THROUGHOUT THE CABIN AFTER TAKE-OFF. THE ODOR DID NOT DISSIPATE AFTER THE APU WAS SHUTDOWN. THE CREW ELECTED TO RETURN TO FIELD. THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE ACTION PENDING. THE APU IS TO BE REPLACED. (OPEN)