Date: 202101
Local time of day: 1201-1800
Location: ZZZ.TRACON, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Other unknown
Flight phase: Initial Approach
Airspace: Class E ZZZ
ATC / advisory: TRACON ZZZ
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Time Pressure; Situational Awareness; Physiological - Other; Communication Breakdown; Workload
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Automation Aircraft RA; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Contributing factors: Staffing
Primary problem: Staffing

Narrative: TCAS RA on arrival into ZZZ [airport]. Assigned descent to 7;000 feet and vectors to final by ZZZ Approach. We reached 7;000 feet and noted approach was extremely busy where the Controller was being stepped on seemingly more than half of her transmissions. While level at 7;000 feet the TCAS noted a proximate target converging from 1 o'clock; 400 feet below. We attempted to contact Approach but there was zero opportunity to get a word in due to the sheer amount of communication on frequency. I advised the Captain PF to 'get ready' while we attempted to locate the aircraft visually. A few seconds later the TCAS noted traffic and ordered a very shallow climb. I announced to ZZZ Approach that we were responding to an RA; but I believe I was blocked; the frequency still jammed with constant communication. A very short time later the controller issued traffic to us and I again advised 'Climbing on RA.' Controller replied 'Roger' I believe and the event was over shortly after. We returned to 7;000 feet and were vectored for the visual; but the controller still had to vector us around multiple VFR targets on our way to the runway. Most significantly we were cleared for the visual approach; but were restricted to flying and intercepting between 5 and 7 NM from the airport due to area traffic. This caused a perceived limitation that pilots are not used to. The CA/PF then overflew the Localizer slightly attempting to maintain these limitations. The aircraft was clearly stable by 1000 feet and we continued in to land; but this was following an incident due to the same cause.Cause was due to the intense level of traffic in ZZZ Approach's airspace. I spoke with a contact at ZZZ [Approach] later who noted the Controller had 15 active aircraft not including the VFR targets attempting to get clearance from the closed airspace; Practice IFR traffic; and VFR flight following requests. The Controller was doing an excellent job and maintained a very professional demeanor throughout. There was just no reasonable way for Controller to maintain communications with the volume of aircraft. I am not sure; but this could have been a result of reduced staffing due to COVID. Maybe there was an East and West ZZZ [Approach] sector available; but no staffing to accommodate. My suggestions would be to either split ZZZ Approach or to draw a new arrival for ZZZ airport to reduce the amount of communications and possible routes needed for the controllers.




Synopsis: Air Carrier First Officer reported an RA event and blocked ATC communications due to possible COVID-19 ATC staffing issues.