Date: 201812
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Anomaly: Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Attendant
When detected: In-flight
Result: General Physical Injury / Incapacitation
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During preflight; I accepted what I believed was a low risk associated with not investigating the link between the horse manure odor coming from both external air conditioning and Pack 1 because I had never experienced or heard of this type of odor being associated with fume events. No one else I spoke to during or after any of these events had ever experienced or heard of this either. Now I know this odor is associated with fume events. In the future; I would not accept an aircraft after a similar series of linked events during preflight without further investigation and correction into the root cause. In this situation; I should have taken the time to pre-plan what to do if Pack 2 produced fume odors during various phases of flight. More generally; I will learn from this experience and incorporate it into risk assessments for accepting deferred maintenance items.The Safety Department should publish de-identified summaries of this and other fume events to allow other crews to learn from this experience as well--particularly that this type of smell can exist.The Safety Department should follow up with the flight attendants to ensure that they receive appropriate medical care and that no disciplinary action is taken against them for calling out sick on the line.[The company] must continue to investigate the causes and prevention of fume events. In particular; the same aircraft had numerous fume events in the several days following this flight. Repeatedly returning this aircraft to service without correcting the root cause is unacceptable.The mechanic attempted to intimidate and interfere with me in the performance of my duties contrary to 14 CFR 91.11 and 121.580; and he refused an opportunity to reconsider and learn from his actions. This indicates his conduct was willful. Mechanics are well-trained and experienced employees held to a high standard. The Company must take disciplinary action against him.Flight Operations Management was not concerned that a mechanic attempted to intimidate and interfere with me; and Management did not provide my requested assistance in expediting transportation to the hospital for the flight attendants. Instead; Flight Operations Management was concerned about whether I had implied liability to passengers; why I had requested ARFF; and whether I was going to be unable to operate my next flight. The Safety Department should discuss with Flight Operations Management the need to provide requested assistance to flight crews dealing with emergencies; and the need to avoid creating undue pressures against flight crews taking the safest course of action.The flight attendants' immediate communication allowed us to correct the problem right away and substantially reduce the severity of the fume event. The First Officer did a great job on this flight; as well as during the entire trip. He completed the abnormal/emergency procedures and communications I delegated to him quickly and correctly so I could focus on landing. Maintenance Control and the other local mechanics took the time to thoroughly discuss the event with me to assist in their troubleshooting. The Captain and First Officer who were scheduled to fly the aircraft next made themselves available to assist us during the aftermath of the event. In particular; the incoming Captain looked after the flight attendants at the gate while I was busy on the jet bridge. All of these personnel should be commended.




Synopsis: A320 Captain reported a fume event on the aircraft resulted in several flight attendants going to a hospital for medical treatment.