Date: 202102
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Final Approach
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Second aircraft: Commercial Fixed Wing
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Situational Awareness; Communication Breakdown; Time Pressure
Second reporter function: Pilot Flying; First Officer
Anomaly: Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate; In-flight
Result: General None Reported / Taken
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: On final [Runway] XXL ZZZ we were paired up with traffic on another runway in visual conditions. I thought the FO had selected TA on the transponder. After debriefing on the ground he told me that he was telling me to set TA on the transponder; but what I heard was transponder is set to TA. Inside ZZZZZ [Intersection] at about 1;200 feet we got an RA Climb. I verbalized 'We got to go.' I surmised that the TCAS RA would be followed by a go-around. My communication was unclear. The traffic was in sight throughout the approach. The FO continued the approach and landed uneventfully. We should have gone around; but after debriefing I understood that the FO thought it might be unsafe to climb and go-around with the other traffic so close.


Second narrative: With the A.P. and A.T. off; I was P.F. on the visual approach to Runway XX.  ATC calls out traffic at our 2 o'clock that will be close to us for another runway.  We call the Aircraft Y traffic in sight and proceed inbound.  Both the Captain and I are wearing masks (COVID); which I believe muffled my request to 'Set to TA only.'  The Captain later said he thought I said 'We're set to TA only.'  The approach continued normally with us going to managed speed; gear down; as we started down the glide slope inside the FAF.  Just after I called for flaps 3 around 1;400 feet AGL; I noted the Aircraft Y a little above us and the appropriate distance to the right joining up with us.  I was still slowing the aircraft at that moment; and the RA went off 'Climb; Climb.'  I asked the Captain 'We are not in TA only?'  He responded 'Well we are going to have to go.'  I momentarily considered going around; but thought continuing the approach was actually the safest course of action when the RA immediately stopped.  We continued the approach and landed uneventfully.  The RA happened the moment the Aircraft Y was joining the other localizer course.  What I should have done is gone around.  Following the RA is the right thing to do unless it is unsafe to do so.


Synopsis: Air Carrier flight crew reported a communication misunderstanding between the pilots resulted in conflict during approach. The Captain stated they were both wearing face masks and that it may have contributed to the miscommunication as their voices were muffled.