Regional Jet 900 (CRJ900)
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 146
Workload; Communication Breakdown; Troubleshooting; Confusion; Situational Awareness
ATC Issue All Types; Conflict NMAC; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Procedure; Human Factors
On the Visual [Runway] XXR approach into ZZZ. Cleared for the approach about 5 miles out; and given a heading 090 to join the localizer. We joined the localizer and got a TA and noticed another RJ (Regional Jet) headed around 150 degrees to join the localizer for [Runway] XXL; which wasn't going to be a factor. We were never left of the [Runway] XXR localizer at any point. We caught the glide slope and headed down while configuring. At this point we received a RA that the [Runway] XXL RJ had blown through the localizer and was right over the top of us; about 300 feet of vertical separation. Captain was flying; he disconnected the AP (Autopilot) and flew the breakout procedure. I told ZZZ Tower we had a RA and he was swamped today so he initially wanted us to go around; to which I said we had flown the breakout and were established on the approach - going around and flying his instructions would've led to a second RA since we were instructed to climb right into that jet that just flew over the top of us. Tower changed his mind and gave us [Runway] XXR landing clearance. ZZZ ATC workload was extremely high and the [Runway] XXL RJ didn't intercept the localizer at all; nor were they aware of the traffic around them (us).High ATC workload and neighboring jet on the other approach had low SA (Situational Awareness).ZZZ workload review and talk to the crew who blew through the [Runway] XXL localizer and crossed into us.
Air carrier First Officer reported flying the breakout procedure in response to an RA triggered by an aircraft on approach on the parallel runway that had overshot the localizer and was directly overhead.