Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 100; Flight Crew Type 10000
Communication Breakdown
Conflict NMAC
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Airspace Structure
While on a vector to a visual to Runway 35R at AUS we were awaiting a turn to the east for left base entry to the runway. At 3000'; and in a turn to 090 degrees we [got a] TA on TCAS less than one mile off our right or south course at the same altitude of 3000' and an urgent call from ATC to the traffic 'Whoever is off San Marcos;' to turn immediately to the south. We are convinced it was the traffic that suddenly appeared; and if we didn't make the immediate turn at 30 degrees of bank to 090 degrees would have resulted in a Resolution Advisory; RA; a near miss or very abrupt maneuver to avoid collision. We feel the extended downwind vector down towards San Marcos due to heavy traffic at AUS with one runway open; resulted in us being close to VFR traffic near San Marcos.
Airline Captain reported a TA which resulted in evasive action to avoid worsening situation.