Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Less Severe
Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification
Aircraft
Traffic Collision Avoidance System Traffic Advisory on Approach. Was Pilot Flying on Flight ZZZ-RSW. Flew the SHFTY 5 RNAV Arrival for the ILS Runway 06. Handed off to RSW Approach. Was instructed to expect the visual Runway 06 with vector over Estero Bay. Given a northwest vector (right-base-to-final) before PONTY intersection. Cleared for the visual by approach inside of TROPC intersection (IAF; D12.6 IRSW) I selected 1500 ft. into the Altitude Window for DOLPN (FAF) and pulled Open Descent. I armed the approach mode. To the best of my memory; I know we were inland of the bay; approximately 2 miles before DOLPN when capturing the localizer. The aircraft was approximately between an altitude of 1700 ft. to 1500 ft. descending when I viewed an intermittent proximate intruder Traffic Collision Avoidance System display. It was visible; gone; visible at first and quite erratic. I was already in the 10 mile range. The First Officer and I immediately began a quick scan for traffic in the area. At about the time the aircraft captured 1500 ft.; we received an aural 'Traffic; Traffic' TA advisory. However; I saw no amber TA intruder symbol but a white proximate traffic symbol showing 1500 ft. below our altitude which was still at 1500 ft. We both continued our scans; and the target disappeared. The First Officer queried the Tower for any known traffic in the area; to which he responded no. We continued the approach; caught the glide slope and landed uneventfully. [The cause was the targets were] erratic; realistically made no sense with the altitudes; not visible to the crew; and unknown to ATC.
Air carrier Captain reported receiving traffic alerts from his TCAS even though ATC reported no aircraft in his vicinity.