Date: 201507
Local time of day: 1801-2400
Location: A80.TRACON, GA
Light: Daylight
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class B ATL
ATC / advisory: TRACON A80
Second aircraft: Large Transport
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Confusion; Distraction; Situational Awareness
Second reporter function: Approach
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance
Contributing factors: ATC Equipment / Nav Facility / Buildings; Human Factors
Primary problem: ATC Equipment / Nav Facility / Buildings

Narrative: I was working AR-V; the final for 26R ATL. We've been using Fusion on final for some time. Today; the LZU ASR feed is in IBI [Interim Beacon Initiative] mode. We were getting a lot of aircraft within 10 miles of the airport jumping; identing; and seeing a lot of false primary targets (that would be there for less than 10 seconds; then disappear). I got Aircraft X in the downwind; and told him 8-10 mile base. He hurried down. I had Aircraft Y fed in the base (too fast; but they were training and it wasn't unworkable). I turned Aircraft X from downwind to base to hit the gap and keep him tight behind his traffic. I waited and waited to see the turn; but didn't. When it was past time to do something; I told him to stop his turn if he hadn't started it. He said he was through a 150 heading. Just after he unkeyed; the tag jumped and showed him southbound. He was in the hole fine; I got Aircraft Y to see the traffic and follow; and all was OK.I said something aloud; and the AR-A controller had been watching the whole thing. I commented something like; 'I must be crazy'; and she said; 'No; I was watching it; I saw the exact same thing'. She commented that she was watching it because it [would create a problem] if the aircraft wasn't turning (exactly why I made the transmission I did). We talked to the third final controller (AR-O); and we all agreed the presentation was unacceptable; and we advised the supervisor on the wall we were going to go to single sensor; ATL ASR on all three final positions.When I got the briefing for the position; the controller on position said there were issues and he was seeing the same thing. He had a lot of histories on his tracks; and you could see them jumping up to .5 miles away from what appeared to be the track the aircraft was taking. I'm all for switching to fusion on final; but when the tags jump this much; it's unacceptable. The replay won't show anything because they look at it on a single sensor (ATL); so it won't see the fused display I was seeing. LZU was brought out of IBI mode as I write this and Tech Ops enabled the Mode-S and then put the finals back on fusion.


Second narrative: While working Final A; I noticed the radar was jumping around more than normal. We were on Fusion which has been known to more noticeably jump than on other sectors. Specifically; I watched two aircraft being worked by Final V. The aircraft on the downwind was turned in front of an aircraft on the base. This operation is normal and usually not a problem. However; it appeared the plane was not turning as directed. The controller questioned the aircraft and instructed the pilot to not turn if he hadn't started the turn already. Then the radar jumped and the aircraft was suddenly squared up on the base. The aircraft was exactly where he was supposed to be and there was no event. This could have led to a serious safety situation. The Final V Controller; the O Controller (the middle final); and I decided to go to single sensor instead of fusion at this moment. To have a radar presentation that is more accurate.


Synopsis: A80 controllers report of using fusion radar on the final sectors.  Controller turns an aircraft into a hole; the aircraft did not turn as the controller thought it would; then jumped showing it on a different then assigned heading.;  The controller had visual separation so all was good separation wise; but didn't like the way the aircraft jumped.  Controller exclaimed and another controller also saw what happened.  Controller thought the jumping of radar targets on final is unacceptable.