Date: 202008
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness; Confusion; Communication Breakdown; Workload; Time Pressure
Second reporter function: Pilot Not Flying; Captain
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft RA; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Procedure; Staffing
Primary problem: Human Factors

Narrative: Diverting around WX (Weather) over ZZZZZ intersection and ATC cleared us to descend from FL380 to FL240. As we approached the WX the Center controller handed us off to the next sector. We checked on descending thru around FL300 and the controller stated he was irritated about everyone stepping on each other. He then called us to see if we were on frequency. We acknowledged his call and about that time I noticed traffic approaching us and they appeared to be at FL290. I was confused as we seemed to be descending right into them and the controller never mentioned them. About the time I realized we were going to conflict with the traffic we received a CLIMB RA (Resolution Advisory). I immediately followed the RA procedure and climbed until we received the 'clear of conflict' message around FL300. Somewhere in that time the controller asked if we were level at FL300 and we told him negative; that we were cleared to descend to FL240. He seemed very confused about our previous descent clearance and our check-on. He then cleared us direct ZZZZZ1 and to descend via the [arrival] which we did. WX deviation combined with a badly timed hand off. Also seems like the center controllers are being tasked with multiple frequencies and sectors and they are very task loaded when traffic picks up. I felt like I was a bit slow to recognize the threat and I could have slowed our descent thru FL300 until it was clarified; but in all reality the speed in which the event occurred combined with the doubt that what you're actually seeing is accurate lead to the delay. I had the range dialed out and at first I thought the traffic must be further away or the controller would have mentioned it. I thought for a few seconds that we must be descending thru the other aircraft's altitude in time to avoid a conflict. I was also working my descent around a large cell and trying to stay above several smaller buildups as we passed it but still keep the aircraft on profile when we rejoined the arrival. Multiple aircraft communicating at once also played a major role in the confusion. As is the case with so many incidents it all came to together at the WRONG time. If it looks like a conflict; change your flight path first and figure it out. It seems obvious to say; but just remembering that stuff just gets missed and ATC misses things just like the rest of us helps keep your awareness up when something just doesn't look right. Too easy to get lulled into a sense of complacency thinking 'that can't REALLY be an aircraft headed right towards us this close to our altitude.' We are always the last line of defense up there and we need to keep that in mind. Always.


Second narrative: We [were] deviating around ZZZZZ intersection due [to] WX (Weather) and we're at FL380 and given a clearance to descend and maintain FL240; and given a new frequency. We checked in but the controller was too busy to respond. Passing through FL310 we got a TCAS alert to stop descent. We complied with the alert. The controller was working too many sectors and was overloaded.Working with minimal staffing and overloading the workforce policy due to the COVID-19 is dangerous to say the least.


Synopsis: A321 flight crew reported ATC was too busy working multiple sectors.