As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OIL SMELL IN COCKPIT ON DESCENT. APU WAS REPLACED AND SHOP DISASSEMBLED GEARBOX AND LOAD COMPRESSOR. ENGINEERING FOUND INDICATIONS THAT THE LOAD COMPRESSOR FRONT CARBON SEAL TO BE THE ROOT CAUSE FOR SMELL IN CABIN. THE LOAD COMPRESSOR CARBON SEAL HOUSING WAS FOUND BULGED AND WITH HEAT DAMAGE TO INNER LIP SEAL RESULTING IN COKING ON SEAL ROTOR. CARBON SEAL, SEAL ROTOR, BEARING AND BACK SHROUD REPLACED.