Date: 201709
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: Marginal
Light: Daylight
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Air Conditioning and Pressurization Pack
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Physiological - Other; Confusion
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On descent into ZZZ; smelled oil vapor fumes. Both FO and I complied with the Smoke/Fumes memory items and donned our oxygen masks. Per FOM; 'If air condition smoke is suspected;' (particularly the part about 'Faulty Equip… Isolate') I turned off pack #1; waited; removed mask; fumes were still present. I put my mask back on; turned pack #1 back on; turned pack #2 off. Waited; then mask off; fumes still present. Mask back on for remainder of flight. Called and asked flight attendants if they smelled any odors in the cabin; but they said they did not.At gate; tried using APU bleed; no odor detected; but switched off after test just in case. The flight attendants seemed to have mild; if any; symptoms. The FO and I had mild headaches; sore throats; and deep breaths caused me to cough. After a teleconference with the Chief Pilot's office; I called to report what happened and ask for advice; but as the incident/flight was completed; they had little interest and/or advice to provide.After troubleshooting the packs using APU air; the mechanics felt that the Left Hand/#1 pack caused the oil fumes. The LH pack was deferred; the FO and I ferried the plane from ZZZ to ZZZ1. The flight attendants stayed and flew ZZZ-ZZZ2 with the passengers on a plane brought in. On the way into ZZZ1; we again smelled fumes and again put on our oxygen masks. The fumes open item was already in the logbook; per the ferry permit; so I didn't need to write it again; but informed the mechanics. Also; the station personnel in ZZZ are outstanding. They communicate well; they anticipate what we might need next and ask us about it. Can't say enough good about them; every time I've been there; but particularly with the fumes event.As the problem was deferred; I don't know the cause. If I'm permitted to speculate; I would say cause was contamination from previous fumes events starting with an oil leak. A fumes event one day; and another later; also on the day of the first fume event led to changing an oil supply line O-ring. After the O-ring replacement; they 'ran the packs for four hours.' Again; only speculating here; but I'm guessing they didn't do a 'pack burn' which involves much higher temperatures and as long as six hours; followed by a filter (ozone?) change. If that is the case; residual oil in the ducts and/or filters is what we smelled. Of course; there could also be another leak; or the residue from the leak in the APU enclosure wasn't completely cleaned up.There are three steps maintenance must take in a fume event: (1) find the source; (2) fix the leak; (3) clean up. I think we are not terribly good at the last step. Pack burn and filter change would have prevented our fumes event.




Synopsis: A320 captain reported during the descent to the destination airport; oily fumes were detected in the cockpit. After donning oxygen masks and accomplishing all appropriate checklists; the flight continued to the destination airport where the aircraft was removed from service.