Date: 201911
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: ATC Issue All Types; Conflict NMAC; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft TA; Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Procedure; Airspace Structure; Human Factors
Primary problem: Airspace Structure

Narrative: Just after sunset; cleared visual approach to XXL in ZZZ. On the base turn; while getting set up on the approach and checking in with Tower; they mention that there will be VFR traffic in the pattern for Runway XY at a nearby airport; ZZZ1. We acknowledge but did not yet see the traffic; and were still turning in. The FO (First Officer) was flying; and set up on a good stabilized visual approach using the ILS as backup. I did see one TCAS hit to the left of course and a few miles away; initially assumed that was our traffic.Closer in; around the FAF; Tower again mentions traffic; but I respond that we didn't see it. I don't recall my exact words; probably negative contact. At this point we look in and see a TCAS hit directly ahead and slightly below. I continue to look outside for the traffic; but don't see it due to lots of lights against the dark ground. Initially I wasn't concerned as we didn't have an RA (Resolution Advisory); or even a yellow colored traffic icon. But at this point I see we are only 400 feet away. My FO was on the ball; and before I could even say anything he leveled off and offset to the right. We were near the fix ZZZZZ at this point; about 800 AGL; and were on course and glide path when we stopped the descent. The closest we saw on the TCAS was 300 feet separation; and the TCAS traffic icon was merged with ours; no separation. We never acquired the traffic visually.If we had not stopped the descent and offset; we would have been much closer than 300 feet. I can't say we would have collided; but it is definitely in the realm of possibilities. I can't emphasize enough how high a threat this situation was. When we landed we queried the Tower; and they just said it was traffic in the pattern; as if it happened all the time. At no point did they display any urgency as to the position of the traffic relative to us.Furthermore; we then realized that the reason we never got an RA was that we had just descended below 900 feet; and TCAS was therefore inhibited. In real time; that had not occurred to us; as we were too busy trying to find the traffic; fly the approach; then make corrections to avoid a collision.Our best guess is that the VFR traffic had just departed Runway XY; was somewhere around 500 AGL and either level or slightly climbing; but still flying towards ZZZ; i.e.; had not yet turned crosswind. This meant it was flying directly in to the glide path for Runway XXL at ZZZ; which we happened to be on at the time. We could not see them due to ground light clutter and deck angle; they were probably flying in the same direction as us and therefore could not see us descending from behind; no RA was available due to altitude inhibit; and we were not getting any kind of avoidance instructions from Tower. We were exactly where we were supposed to be; in full communication with ATC; yet still were placed in a dangerous situation.


Second narrative: Cleared visual to XXL at ZZZ and went direct FAF to intercept final; AP (Autopilot) and ATR (Auto Throttles) off. On base turn to final; Tower called out VFR traffic off Runway XY from a local airport. Turned out to be ZZZ1. Captain acknowledged traffic call with negative contact. Since we were configuring at the time; we did a quick scan and didn't see traffic although TCAS showed traffic off to left of centerline with no altitude. Once approach stabilized at the GSI (Glide Slope Indicator); FAF = ZZZZZ1; Tower again calls out traffic departing Runway XY ZZZ1 and Captain replies; negative contact. TCAS shows traffic 1000 ft. or more below. Since it was dusk and deck angle was 2.5 - 3 degrees; aircraft was difficult to see amongst cultural city lighting.As we continued approach; altitude between aircraft decreased to 500 ft. on the TCAS. I then offset slightly to the right of course and started to level off; slightly inside of ZZZZZ; hoping the Captain could gain visual contact. When I leveled off; approximately 800 ft. MSL; TCAS showed traffic at 300 feet below and climbing. TCAS symbol merged slightly off to our left and 300 feet below. No RA (Resolution Advisory) or TA (Traffic Advisory) sounded. Once clear of symbol on TCAS; I continued approach from approximately 1 dot high on GS and quickly stabilized prior to 500 feet. We landed uneventfully. On taxi-in; I asked ground about traffic we encountered on final. They seemed to feel it was not out of normal operations. After Tower cleared us the visual; they really didn't point out traffic again. Even if we had been on an instrument approach; I don't think Tower would have provided separation.Difficult to say but if we had not leveled off and if the departing traffic continued to climb or fly extended centerline off ZZZ1; a collision could have occurred. We fell into the trap of relying on Tower for separation; thinking we would visually acquire the traffic and that the traffic would turn crosswind. Unfortunately; none of these occurred. Without reviewing the radar tapes; hard to say how close we were - departing aircraft was probably a high wing aircraft; on extended centerline; climbing and we are overtaking it; and we have a high deck angle making visual acquisition extremely difficult at dusk.Reviewing company FM (Flight Manual) and FOM and open source documents related to ZZZ1. FM - no RAs below 900 feet. No TAs below 400 feet; so I figured that would have triggered but it didn't. FOM - visual approach provides guidance when following an aircraft to the landing runway but does not provide traffic resolution for other scenarios. ZZZ1 - Remain less than 700 feet MSL due to traffic on XXL to ZZZ. Extended centerline off ZZZ1 at 700 feet puts you in direct conflict with traffic on ZZZ XXL.


Synopsis: A320 Captain reported experiencing a near mid-air collision during approach to landing.