Date: 201903
Local time of day: 1201-1800
Location: PSP.Airport, CA
Flight conditions: VMC
Light: Daylight
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class D PSP
ATC / advisory: TRACON SCT
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: Pilot Not Flying; Captain
Anomaly: Conflict Airborne Conflict
Detector: Automation Aircraft RA; Person Air Traffic Control
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: RNAV visual arrival into PSP for Runway 31L. Approaching CEKMA intersection; ATC called out traffic (north bound) and gave us present heading (265 degrees) & level off at 5000 feet. Traffic was spotted off our right and ATC cleared us for visual. Started descent/ configuring and turned toward ULALE intersection. Lost traffic and then it appeared along our projected path and TCAS conflict alert and resolution resulted. TCAS flight path resolution was followed and traffic appeared below us; flying toward us and underneath us. Aircraft changed direction in uncontrolled airspace as we were approaching PSP airport flying RNAV visual arrival. Mountains on both side of valley congest arrivals and local traffic. ATC communication for all traffic in the valley; near PSP airport would help. Giving VFR traffic greater separation in case of course reversals. Don't lose sight of traffic on visual separation.


Second narrative: Cleared RNAV visual 31L PSP. Between CEKMA and ULALE on 265 course. SoCal noted traffic at unknown altitude headed north. I felt uncomfortable with the proximity of the traffic and requested a 240 heading; mindful of the rapidly riding terrain to our west. Approach cancelled. Assigned 4000ft. Traffic located visually; headed away from us. Re-cleared RNAV visual 31L. Took a heading direct ULALE and began appropriate descent. Approaching ULALE; sudden RA (Resolution Advisory) and 'Climb' 'Climb'. TCAS (Traffic Collision Avoidance System) noted traffic 200 ft below us; within a mile; and headed in our direction. Complied with RA. Traffic passed 200 ft directly below us. Re-cleared app. Normal Landing.The offending traffic was operating legally in Class D airspace and not using flight following.After we sighted the traffic; and at the same time we turned to ULALE to resume our approach; the traffic made a sudden left turn (initially away from us) to south; 'as though they were cutting donuts in the sky'. That left them headed exactly toward us and 200 ft. below us. This explains the sudden RA with no preceding TA (Traffic Advisory).Why; in spite of Controller concerns; is the area around PSP still Class D? This airspace must be upgraded so that both flight following and transponder are required. An airliner with approximately 160 souls on board; while complying with all ATC instructions and taking proactive action to avoid traffic before TCAS alert in an area of onerous terrain came within 200 ft of midair collision. Change the airspace designation ASAP at PSP before lives are lost.


Synopsis: Air carrier flight crew reported an airborne conflict with non-participating traffic while on approach to PSP.