Date: 202008
Local time of day: 0601-1200
Location: ZZZ.ARTCC, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Distraction; Time Pressure
Second reporter function: Pilot Flying; Captain
Anomaly: Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Passenger Misconduct
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: While on descent into ZZZ I received a call from one of the flight attendants alerting me to non-compliance issue that was being had with a couple passengers in regards to our mask policy. I relayed the information to the Captain and we discussed our course of action. The delinquent passengers were seated in row 12 and we made note of that and repeated it several times in our discussion. I then switched to operations to explain the situation to them. While with operations ATC cleared us to cross ZZZZZ at 16;000 feet. I was busy with operations and did not hear this transmission. Most likely due to the primacy of '12' in our minds the captain set 12;000 feet in the altitude alerter. Once I had finished with operations the Captain and I finished the discussion of how to handle the non compliance. ATC then had us switch frequencies. The new Controller asked us what altitude we had been given and that is when the mistake was realized. We temporarily leveled at 15;000 feet before ATC cleared us lower. ATC's reaction was that it was not a concern. The remainder of the descent and landing were uneventful. All of this occurred in a very short period of time.The most obvious take away from this is aviate; navigate; and communicate. The altitude verification process was missed because I never heard the call and we jumped right into the discussion of what to do with the passengers rather than the captain alerting me to the changes.


Second narrative: ATC cleared us to cross ZZZZZ at 16;000 feet and 250 knots. Simultaneously; my First Officer (FO) was on the interphone with a Flight Attendant regarding passenger's non-compliance of our face mask rules. Said passengers were in row 12; and I assume that for that reason; I set the altitude alerter to 12;000 feet; not 16;000 feet. The error wasn't discovered until we were handed off to approach; descending through about 15;500 feet. We ended up leveling momentarily at 15;000 feet. ATC ensured us it was no big deal; as there was no conflicting traffic. Rest of approach and landing uneventful.As this happened in the descent phase and us getting fairly close to our destination; and given the new directive to contact Dispatch and Station regarding non-compliance; I let myself get rushed contacting Dispatch via ACARS; and my attention diverted from verifying new altitude/speed with my FO when he got off the interphone.


Synopsis: Air carrier flight crew reported an altitude deviation due to distraction. The pilot crew was listening to a Flight Attendant describe details of a non-compliant passenger regarding the face mask policy.