Date: 202009
Local time of day: 1801-2400
Location: SDF.Airport, KY
Flight conditions: VMC
Light: Daylight
Aircraft: Medium Transport; Low Wing; 2 Turbojet Eng
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class C SDF
ATC / advisory: Tower SDF
Second aircraft: Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Second reporter function: Local
Anomaly: Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Air Traffic Control Separated Traffic
Contributing factors: Procedure; Manuals; Human Factors; Chart Or Publication; Airspace Structure
Primary problem: Airspace Structure

Narrative: Aircraft Y called Approach and said 'Louisville Approach this is Aircraft Y we are down here over the river at 1500 under your airspace just letting you know we are here'. I typed in a local VFR flight plan and gave Aircraft Y the squawk code. I scanned the area for a 1500 foot target somewhere near the river and saw one by 6 mile island at 1600 feet indicated. As soon as Aircraft Y tagged up at 1500 feet indicated the target was Collision Alert Alarming with Aircraft X who was descending through 2000 feet on a visual approach to Runway 17L. I feel I did not have time to use the prescribed phraseology and needed to get Aircraft Y turned immediately. I told Aircraft Y traffic was on a 4 mile final for 17L and he needed to turn east bound immediately. Aircraft Y said he had the traffic in sight and wanted to fly down the river eastbound. Aircraft Y was told to maintain visual separation and proceed as requested. This facility is in dire need of Class B airspace. Due to the proximity of SDF to many small uncontrolled airports along with an active army airport it is exceedingly common that our; mostly heavy jet; traffic has to be vectored around small GA aircraft and military helicopters. We have a towered field less than 4 miles from SDF and a very active uncontrolled field on a 10 mile final when we are south. Along with restricted airspace within 12 mile final when we are north. These cause many aircraft who are landing at the uncontrolled field or aircraft that are avoiding the restricted airspace to fly through our finals. Changing our airspace to Class B would help keep those that request radar services safer and decrease delays while keeping unpredictable small aircraft who do not want radar service safe from wake turbulence dangers away from the bulk of our heavy jets.


Second narrative: Aircraft X was on a visual approach to Runway 17L just outside the Class C surface area. I had already cleared them to land and noticed a VFR target at 1500 feet just outside the Class C surface area headed towards Aircraft X. The VFR target was technically legal as they were just outside the surface area and under the shelf. As Aircraft X reached 2000 feet I pointed out the traffic then saw the VFR target get tagged as Aircraft Y by the Departure Controller. Right after that Aircraft X reported an RA (resolution advisory) climb. Had the landing aircraft been a heavy jet; which is the majority of our traffic; Aircraft Y would have been in significantly more danger. This happened due to the poor design of our Class C airspace and lack of Class B airspace.This facility is in dire need of Class B airspace. Due to the proximity of SDF to many small uncontrolled airports along with an active army airport it is exceedingly common that our; mostly heavy jet; traffic has to be vectored around small GA aircraft and military helicopters. We have a towered field less than 4 miles from SDF and a very active uncontrolled field on a 10 mile final when we are [landing] south. Along with restricted airspace within 12 mile final when we are [landing] north. These cause many aircraft who are landing at the uncontrolled field or aircraft that are avoiding the restricted airspace to fly through our finals. Changing our airspace to Class B would help keep traffic to our main airport along with small aircraft that request radar service safer and decrease delays while keeping unpredictable small aircraft who do not want radar service safe from wake turbulence dangers away from the bulk of our heavy jet traffic.


Synopsis: SDF TRACON Controller and SDF Tower Controller reported a close airborne conflict between an IFR aircraft conducting an approach and a VFR aircraft in the vicinity of the final approach course which had just contacted the TRACON Controller. Both Controllers insist the airport needs more restrictive airspace to protect aircraft on the Instrument Final Approach course.