Date: 201910
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
ATC / advisory: TRACON ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Distraction; Situational Awareness
Anomaly: Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On approach to ZZZ noted a very faint odor from the ventilation; commonly referred to as a 'dirty sock' odor or variation thereof. The odor manifested itself at a late phase of flight near and below 10;000 MSL so little was done to attempt to isolate the cause in-flight. My primary concern at that point was to simply land the aircraft given we were on downwind and the odor was very slight. The FO [First Officer] elected to don his O2 mask while I did not. In my estimation this was a very minimal fume event and in the 20 years I have been flying the A320 series of aircraft as a Captain I have experienced multiple odor/fume events in all phases of flight ranging from barely noteworthy to severe. After landing and during taxi we selected the left pack OFF and the odor dissipated; although I cannot say with certainty that the left pack was the source due to the numerous variables involved. Upon arrival at the gate the #1 FA [Flight Attendant] said that he had noticed the odor but my impression was he was not overly concerned. I do not recall the other FAs expressing concern at the time. I asked two deadheading [airline] pilots if they had perceived the odor and they replied they had not noticed anything out of the ordinary during the flight. The outbound flight crew was awaiting our arrival so I advised them of the faint odor and that in my personal experience I did not feel the event was significant enough to warrant a write-up at that point. I also advised them if they had any concerns operating the return flight to ZZZ1 I would make an immediate entry into the logbook and notify Maintenance Control. Based on the information provided they expressed no concern and advised that if they had any issues with odors/fumes while on APU or engine bleed they would advise MX [Maintenance]; file a fume report and make the necessary logbook entry. At that point we departed the aircraft/airport for the layover hotel. Cause: unknown; but the aircraft was unaffected until the last phase of descent at lower altitudes. Suggestions: fume events seem to have become an industry-wide issue; with claims ranging from headaches to neurological damage; debilitating illness as a result. Sensitivity to these odors/fumes also seems to vary widely between individuals. Unfortunately; it seems any aircraft utilizing traditional bleed air-driven packs are susceptible to odor/fume events; and the causes of odors/fumes are numerous and diverse. Elimination of these events will likely fall to the implementation of new technologies such as those present in the 787 aircraft. None of this is meant to cast aspersion on the effect of odor/fume events and rest assured I have no reservations in documenting noteworthy odor/fume events. However; the perceived severity of these events can be subjective. I reiterate that in my experience this event; while detectable; was transitory and minimal.




Synopsis: A319 Captain reported 'very faint dirty socks odor' on descent to landing.