Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Distraction
Conflict Airborne Conflict; Inflight Event / Encounter Unstabilized Approach
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Executed Go Around / Missed Approach
Aircraft; Airspace Structure; Human Factors; Procedure
On final approach for XXR into ZZZ; Tower advised of traffic off our left. The traffic could not be visually identified. The traffic appeared to be operating in Class B airspace but was not on frequency with Tower. As we descended on short final we received two traffic advisories. At approximately 800 feet AGL we received a resolution advisory instructing us to climb. The Captain was PF and I was PM. The Captain initiated a climb to resolve the conflict. After the climb was initiated a stabilized approach to a landing in the touchdown zone was no longer assured. At that point the safest course of action was to execute a missed approach and the Captain proceeded to do so. We executed the missed in compliance with ATC instruction and landed uneventfully on the next attempt.Lately I have noticed an increase in small single engine GA aircraft doing landings and pattern work at ZZZ and transiting the Class B airspace. With the drastic decrease in fuel prices and lower 121 traffic volume in and around ZZZ it seems there has been a corresponding increase in small aircraft.
I was the Captain on Aircraft X from ZZZ1 to ZZZ. We were on a visual approach to runway XXL. Descending through about 2;000 feet Tower gave us a traffic alert regarding Aircraft Y that was over the shoreline heading towards us but was not talking to Tower. Immediately following that statement from tower we got the 'TRAFFIC; TRAFFIC' alert from the TCAS. We made the final step in configuring for landing; descended below 1;000 feet; got the 1;000 foot chime and almost immediately got another 'TRAFFIC' alert from the TCAS. Shortly after; we received a Climb RA at about 800 feet; but neither me or my First Officer had had the traffic in sight so I elected to execute a missed approach instead of trying to salvage the visual following an RA. We got vectored around and landed safely with no further incident.
Air carrier flight crew reported being on final to a Class Bravo airport and having to go-around due to a small aircraft that was not talking to Tower; which caused the airborne conflict.