Date: 202103
Local time of day: 1201-1800
Location: EUG.TRACON, OR
Flight conditions: VMC
Light: Daylight
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E ZSE
ATC / advisory: TRACON EUG
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Situational Awareness; Workload
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Other / Unknown
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
Contributing factors: Airport; Airspace Structure; Procedure
Primary problem: Airport

Narrative: Aircraft X checked in from 40 miles north of the airport requesting opposite direction arrival Runway 14.  I coordinated with Medford Tower and they denied it due to an aircraft with a controlled departure time even though the departure would not have been a factor. I told Aircraft X unable and they requested the RNAV 32 Approach via SAMIE so I cleared them for the approach via SAMIE at or above 10;000 feet. As Aircraft X was following the course a VFR tag popped up near the approach path about 11 miles south of the airport (they appeared to depart from an uncontrolled airport that is directly in the approach path) so I issued traffic multiple times and gave Aircraft X an altitude restriction for traffic but when Aircraft X got closer to the unidentified target the target climbed and turned at the Aircraft X resulting in a TCAS RA at which point the Aircraft X climbed and eventually requested an altitude to maintain and wanted lower for a Visual Approach. Due to terrain I was unable to descend them low enough and had to issue vectors around for the ILS 14 Approach which the aircraft conducted and landed safely. I then had another arrival requesting the RNAV 32 Approach and the unidentified target was still a factor.The RNAV 32 Approach flies directly over an uncontrolled airport that is frequently used by VFR aircraft and also follows a very busy VFR area over a highway that aircraft not on flight following use for navigation. This approach is inherently dangerous due to the number of aircraft that fly along it's path without communication with Approach Control and because it flies through a valley between mountainous terrain giving ATC few options to avoid conflict with aircraft that can't be seen by our radar until reaching above 4;000 feet. I recommend that Medford airport should be allowed to advertise Runway 14 arrivals with Runway 32 departures. Whoever decided that we can't advertise that needs to come have a look at the arrival/departure procedures available at Medford and give an actual answer as to why? Runway 32 arrivals are much more dangerous to aircraft than Runway 14 due to mountainous terrain; and Runway 14 departures are far more dangerous when also arriving Runway 14 because the departure procedure for Runway 14 turns aircraft around directly in the face of aircraft arriving runway 14 creating an opposite direction conflict with FAR less control and restriction than we would have with a 14 arrival and 32 departure. Opposite Direction Operations requires a 10 mile cutoff where the opposite direction conflict created by a Runway14 arrival with a Runway 14 departure does not allow us to turn aircraft until a much higher altitude resulting in risky behavior.  Runway 32 even has a departure procedure that provides safe divergence from opposite direction arrivals called the EAGLE 6 Departure. Until someone actually comes to the facility and understands the dangers of not being able to advertise Runway 14 arrivals with Runway 32 departures there will be many more close close calls that could have been safely prevented. It is an easy fix with amazing benefits for controllers; pilots; and preventing air carrier delays.




Synopsis: EUG TRACON Controller reported an unidentified VFR aircraft climbed into confliction with an Air Carrier on an RNAV Approach causing the Air carrier to respond to a TCAS/RA. The reporter states this is a recurring traffic situation in their airspace