Date: 202101
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked; Cruise; Taxi
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Physiological - Other; Troubleshooting; Other / Unknown; Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Passenger Misconduct
Detector: Person Flight Attendant; Person Other Person
When detected: Aircraft In Service At Gate; In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors; Environment - Non Weather Related; Company Policy
Primary problem: Environment - Non Weather Related

Narrative: I was deadheading on Aircraft X. I identified myself to the A Flight Attendant (FA) (as I always do) as a safety and security asset.The flight was nearly full.  During boarding a man who I later learned was Mr. X approached my seat.  He was wearing a camo gaiter around his neck which was partially covering his mouth but was not covering his nose. As he approached; I identified myself as a crew member and politely asked him to pull his mask up over his nose.  He complied but said that I should pinch my mask tight over my nose.  I didn't quite hear what he said so I queried him.  He said; 'You should pinch down on your nose to close the gap at the top of your mask.'   My mask was an NP95 which had no gaps anywhere around my face.  It was my sense that the man was being sarcastic and antagonistic.  I said nothing further to him.I advised the FA A what happened before we pushed back.  She told me that the man had boarded without his face covered and was told to cover his face.  Thus he had pulled his face covering off his face between the time he boarded (when he was told to put it on) and the time he approached me; which was no more than thirty seconds. He clearly had no intention of complying with the mask policy.  FA A asked me to brief the Captain about the incident and asked if I would talk to the CSR agent whom she wanted to speak with Mr. X. I agreed.  Before departure I walked into the jet bridge and spoke with FA A and the CSR.  I briefly explained what I observed and what he said to me then I went back onto the airplane and took my seat.  A short time later I observed Mr. X walk back down the aisle past me.Sometime during the flight FA A advised me that Mr. X had been [violating other regulations].  She advised me that Mr. X demanded to know the crews names (including mine) but that she did not give him any names. She was clearly concerned about this and I could see how his actions were distracting to the flight crew and were thus interfering with their duties.  She told me that she was going to have CS meet the aircraft and asked me to stay as a witness.  FA A as well as the rest of the inflight crew were nothing but polite and professional the entire flight; when I observed her dealing with Mr. X or otherwise.After leaving the aircraft I was standing in the jet bridge and spoke with a CS Supervisor.  Mr. X walked by me and said in an aggressive and hostile tone; 'I want your name.'  I told him that I could not give it to him and that I could not speak with him about this matter.  He again demanded my name and moved closer to me.  I backed up.  He then raised his camera and said; 'I'm taking your picture.'  I stated; 'Do not take my picture.'  He said; I'm taking your picture.'  I quickly turned around and walked around the jet bridge corner toward the aircraft door.   I do not know if he took my photograph or not but felt that his forcing his camera in my face was one of belligerence; hostility; and aggression.  I felt threatened.  All of this simply because he was asked to properly wear his mask.  After the CSR Supervisor and Mr. X walked into the terminal; I remained in the jet bridge as I did not want to encounter Mr. X again.When the CSR Supervisor walked back onto the jet bridge; I explained to her that I could not have my photograph taken and suggested that if he loitered around the terminal waiting for me that she please call law enforcement.  I asked her if she felt he was being hostile and or belligerent.  She agreed that he was.  After some time; Mr. X left the area; and I departed the terminal.Based on his behavior and actions I would strongly urge that Mr. X is not allowed to fly on our airline in the future.




Synopsis: Air carrier Captain deadheading on a company flight reported a passenger would not conform to the face mask policy and was hostile; aggressive; belligerent towards the flight attendants.