Date: 202109
Local time of day: 1201-1800
Location: SAT.TRACON, TX
Flight conditions: VMC
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E SAT
ATC / advisory: TRACON SAT
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Workload; Communication Breakdown; Distraction; Time Pressure
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Inflight Event / Encounter CFTT / CFIT
Detector: Automation Aircraft RA; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Contributing factors: Airspace Structure; Human Factors; Procedure
Primary problem: Airspace Structure

Narrative: At approximately XA:40Z; Aircraft X; an Air Carrier; was being vectored for the ILS RWY 13R at SAT. He was fourth in the sequence to the airport so I had to bring him out to roughly a 15 mile final. This takes the aircraft over 5C1; a satellite airport in our airspace.  At the time I turned Aircraft X base; there was no traffic in the vicinity of the airport.  However; once the aircraft was established on the base and descended him to the Minimum Vectoring Altitude (3100 feet); I noticed a VFR target departing south/southwest off of 5C1.  As this aircraft was headed southbound and was much lower than my aircraft I cleared Aircraft X for the ILS approach to go behind and above the VFR aircraft. I issued traffic to Aircraft X and I thought he said 'Not in sight'; however; the language barrier makes it difficult to tell.  As Aircraft X became established on his intercept vector; the VFR aircraft continued to climb into conflict with Aircraft X so I cancelled the approach clearance and climbed Aircraft X to 4000 feet.Unfortunately; the VFR aircraft continued to climb as well.  I then instructed Aircraft X to turn Right Heading 180 immediately to avoid the VFR traffic. The first transmission was blocked so I repeated it.  I also called in the blind to the VFR aircraft and issued traffic hoping they were at least listening to our frequency.  At this point the VFR aircraft turned directly into Aircraft X.  Aircraft X then responded to a TCAS advisory and descended below the Minimum Vectoring Altitude.  I advised him to let me know when was able to take an intercept vector back to the ILS.  Aircraft X asked for information on the VFR aircraft; but the aircraft was not equipped with ADSB-out (Automatic Dependent Surveillance Broadcast) so no information was available. The closest the aircraft came to each was .42 miles and 200 feet.This is one of many reports on the dangers of the proximity of 5C1 and their operations to SAT.  We have asked for 'C' extension to encompass the airport/aircraft that operate there.  Unfortunately; the pilots there don't want to be restricted and even with multiple attempts at outreach with them to show and explain the situation we're dealing with here there are still many there who simply do not care of the dangers they can pose to aircraft landing at SAT. Additionally; even though the pilot of the VFR aircraft turned directly at the airliner we have no way of identifying or correcting his/her poor decision.  The core tenet of VFR is 'see and avoid' and this pilot did not do one or the other.  Either he/she didn't see the aircraft and turned into Aircraft X or saw him and did not adequately avoid them.  Either way; there is no way to report this to anyone nor can we make contact with this individual to educate them on the seriousness of what happened.We have discussed the possibility of a departure procedure that would keep aircraft lower or at least at a fixed altitude so we can ensure separation; however; this wouldn't be compulsory and the same issue explained above would most likely take place. At this point unless there is a catastrophic disaster nothing will change.  I understand the airspace change is happening; but it has been happening for 2 years now and there has been very little movement to actually fixing the issue.  It is a macabre outlook; but this is the situation we're dealing with every day to our primary runway and the agency that is tasked with preventing these sorts of disasters; has thus far been unable to affect any meaningful change to prevent this awful scenario.




Synopsis: SAT TRACON Controller reported an unidentified aircraft departed 5C1 airport underneath the SAT ILS final approach course and climbed into confliction with an Air Carrier. The Controller climbed and vectored the Air Carrier to avoid the traffic but the Air Carrier responded to a TCAS/RA and descended below the Minimum Vectoring Altitude.