Date: 201512
Local time of day: 1801-2400
Location: P80.TRACON, OR
Light: Night
Aircraft: Widebody; Low Wing; 3 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Final Approach
Airspace: Class C PDX
ATC / advisory: TRACON P80
Second aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Confusion; Situational Awareness; Distraction
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Air Traffic Control; Person Air Traffic Control
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors; Environment - Non Weather Related; ATC Equipment / Nav Facility / Buildings; Procedure
Primary problem: ATC Equipment / Nav Facility / Buildings

Narrative: I was informed of a wake remnant error between Aircraft X and Aircraft Y by my supervisor. After reviewing the replay it appeared that there was an erroneous track hit by TARP [Traffic Analysis and Review Program] that caused it to flag a wake remnant error. The track was steady on about a 190 heading and then stitched east for about 1 hit and then corrected itself back to the previous track. If not for this one erroneous stitching issue from the Fusion radar I don't believe it would have been a wake remnant issue. There are multiple issues here. The first being we as controllers have no way to track wake remnant. TARP can but STARS (Standard Terminal Automation Replacement System) can't? How can we be expected to run a safe and efficient operation without the proper tools to track something like this? You would think the 'most advanced' air traffic system in the world would be able to fix this issue. Second; is every stitching (Fusion radar jumping and then coming back to primary location) issue with Fusion radar being treated the same way? If a target established on final stitches across final and is below minimum separation with another aircraft on an adjacent final is that a loss of separation? We've been told that it is not. Why is my situation different? P80 only has one ASR (Airport Surveillance Radar) feeding into Fusion. They also have one ASR and the rest are long range radars. Are other facilities with more ASR's feeding into fusion having these same issues? Single site radar should not be more accurate than Fusion but that's the way it seems. It's coming to the point where controllers may start saying their equipment is unusable and refuse to take position because they can't trust the reliability of said equipment. Give controllers some way to track wake remnant on their scope. Define wake remnant in the 7110.65. Give QA (Quality Assurance) some room to use common sense and disregard erroneous TARP hits due to stitching and poor radar coverage or at least annotate that the loss of separation could be erroneous. Clarify why some TARP hits due to radar stitching are errors and others are not. Put another ASR in the P80 airspace to allow fusion to function more properly. I understand this will never happen but the way we are using Fusion at P80 is not the way it was intended.




Synopsis: P80 Controller reported a wake turbulence remnant issue. Controller reviewed a replay that appeared to be a fusion radar stitch. Controller wondered how he could be charged with an operational error when he had no tool available to verify wake remnant.