Date: 202103
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
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: Troubleshooting; Physiological - Other
Anomaly: 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 Attendant; Person Flight Crew
When detected: Pre-flight; Routine Inspection
Result: Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem; General Work Refused; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: Approximately 5 minutes at gate; after gate return; while discussing Weight and Balance issue with ramp supervisor; #1 FA (Flight Attendant) said #2 FA reported electrical burning smell that had since dissipated. We called for Maintenance. Maintenance techs arrived quickly within 5 minutes and said no odor/smell noticed by them.Asked for FA 2 to come to flight deck and explain the odor. She again said it was a burning smell and it was still there though not as strong. She said she could 'taste' it. At that point I told gate agents we would deplane the aircraft. I advised FA's and made an announcement for Passengers to deplane. I asked 2 to fill out a form and called the Dispatcher who said he would look for another plane.Passengers off aircraft; went to back and discussed issue with FAs. #4 now said he also could 'taste something metallic'. I advised FAs to leave the aircraft also while we talked to Maintenance. I inquired if anyone wanted or needed medical attention to which the answer was 'no' by all. I then completed and submitted the smoke/odor form with information gained while discussing the situation with FAs in the jet bridge. They now said there had also been a musty smell. Logbook entry made and discussed with techs. All fume/odor event SOPs completed.A new aircraft was assigned for the flight. While waiting for the cleaners in the jet bridge with the FAs both 2&4 said they had tightness in their foreheads and 4 said his taste was still a little metallic. I asked them to call for FA supervisor while I also asked the gate agents to do the same so we could evaluate everyone's fitness for duty.I called the Duty Chief; and explained the situation. I then discussed the situation with [name]; FA supervisor via gate telephone who said another supervisor was on her way to the aircraft. FA supervisor; came to the aircraft immediately and talked to the FAs who said they were physically ok. We then all discussed the issue together and all FAs said they were fit for duty and felt better.We arrived in ZZZ1 after an uneventful flight and the First Officer and myself waited for the FAs to make sure they were still feeling OK. Everyone said they were fine.Possible cause perhaps a tailwind on engine shutdown




Synopsis: A321 Captain reported a fumes event during pre-flight which eventually resulted in an aircraft swap and an uneventful flight.