Date: 202001
Local time of day: 1201-1800
Location: ZZZ.TRACON, US
Flight conditions: VMC
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class E ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: APU
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Second reporter function: Captain; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Attendant; Person Flight Crew
When detected: In-flight
Result: Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Inbound crew from ZZZ1 noted nothing abnormal about aircraft on arrival. Due to weather delay at ZZZ1 and subsequent maintenance delay for an unrelated fuel leak from left wing water drain; aircraft was cooled by APU bleed air for roughly 3 hours with nothing unusual noted. We switched off the APU roughly 15 minutes before departure and operated on engine bleed air with nothing abnormal noted. Shortly after takeoff; I began to notice an odor I would describe as a musty wet sock smell coming from the air ducts and commented to the Captain. We both felt it may have been something in the air around ZZZ. Passing 10K; the lead Flight Attendant contacted us about a strange odor in the cabin. I asked him if he noted any smoke or other vapor; he did not. I asked if he or anyone else was feeling ill; he said no; but that the Fight Attendants in back felt hot. I turned all temperature control knobs full cold and the Captain selected high flow. I told the lead Flight Attendant to notify us if he or anyone began to feel ill. I checked the air conditioning; electrical; bleed air; and pressurization pages; all were normal. We had no ECAM notifications and all systems appeared to be operating normally. The Captain and I noted the odor seemed to lessen as we climbed and approached cruise altitude; so we continued. I elected to don my oxygen mask as a precaution. We both referenced the smoke/fumes & removal of smoke/fumes checklists (80.1 &amp; 80.16) in the QRH as a precaution. We did not feel the situation warranted actions recommended in either checklist; particularly since the odor appeared to be dissipating. We continued to ZZZ1; but noted a return of the smell as we began our descent; so I made an MRM entry noting a musty wet sock smell. We landed uneventfully and I immediately started the APU; transitioned to APU bleed air; and shut down the engine bleeds. We noted an improvement in the smell after this was done. We informed maintenance & the outbound crews of our concerns. Maintenance informed us that this aircraft had a history of this situation. We noted there was nothing in the maintenance section of the flight plan regarding unusual odors and that the inbound crew did not note anything unusual.


Second narrative: The inbound crew noted no defects. Our flight was delayed due to weather in ZZZ1 and a ground stop; so the aircraft was cooled by the APU for about three hours. The APU was shut down after second engine start shortly before takeoff from ZZZ. After takeoff and climbing out of ZZZ we both noted an unknown faint odor and commented that it could be smog. Climbing through 10;000 feet noted that the odor it was still present and seemed like a wet sock or gym like odor. No smoke; fumes; or other abnormal indications were present. We established contact with the purser/lead flight attendant who reported that he also could smell the odor and it seemed to be throughout the cabin. The lead was asked to investigate and report any smoke; vapors or fumes; any complaints of feeling ill; and relay any information from the other flight attendants as well.After a short while the odor seemed to dissipate but was still perceptible. Further contact with the lead flight attendant confirmed that the odor was dissipating but still perceptible in the cabin and the aft cabin was reported as having a warm air temperature; so we took steps to cool the cabin. The flight attendants were advised to keep us informed of any changes; or if the odor strengthened or any other changes occurred. No smoke or fumes were evident in either the cabin or the cockpit. There were no abnormal system indications or EICAS messages. (Electrical; Hydraulic; Engine; ECS; etc. were all normal). Although still perceptible; the wet sock smell seemed to be going away and under control. As a precaution; we reviewed the Smoke/Fumes QRH and Smoke/Fumes removal QRH but did not execute as there was only the lingering odor that was continuing to dissipate. The first officer did don his oxygen mask for a time as a further precaution. We did not feel that since the odor seemed to be dissipating and under control; the Smoke/Fumes removal QRH was necessary at that time. We elected to continue the flight.At cruise we contacted the lead flight attendant on three occasions; and he continued to report that the odor was lingering and perceptible but not increasing; and no other changes or feelings of illness reported. Descending through approximately 6;000 ft on approach and until touchdown the odor returned and continued to be present and strengthening on short final until landing. At this point we were already cleared the visual to XXL at ZZZ1 positioned to land immediately. We continued to a normal landing. After landing we switched to APU bleeds and the odor began to dissipate quickly. The odor did not return but was noted by the technician who met the aircraft. We did not feel that there were fumes present; just the annoying odor. The condition was entered in the log and maintenance was briefed. The maintenance technician asked he cockpit and cabin crew to fill out forms indicating specific engine; pack indications; whether the aircraft had been deiced; ground air used; engine; hydraulic fluid levels; etc.The technician informed us that the aircraft had a history this although there was no note of this in the recent log history.After the flight the flight attendants all noted that when the odor returned on the approach; it was stronger than before. While they reported to us during the flight that they did not experience any feelings of illness; now that it was over they felt it would be a good idea to get a medical checkup in ZZZ1.The FODM was briefed as soon as practical after the flight. Although fumes were not selected above as an element of this report; it was our determination that it was more of an odor and did not reach the strength of a fumes definition or event.


Synopsis: A319 flight crew reported a fume event during initial climb which dissipated only to return on descent at destination.