Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Time Pressure; Situational Awareness; Physiological - Other; Communication Breakdown; Workload
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Staffing
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.
Air Carrier First Officer reported an RA event and blocked ATC communications due to possible COVID-19 ATC staffing issues.