Date: 201507
Local time of day: 1801-2400
Location: ZME.ARTCC, TN
Light: Night
Aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZME
ATC / advisory: Center ZME
Reporter organization: Government
Reporter function: Enroute; Handoff / Assist
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Human-Machine Interface; Situational Awareness; Distraction; Confusion
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Equipment / Tooling
Primary problem: Equipment / Tooling

Narrative: A probable equipment issue; my R-side & I both observed a mode-C intruder target appear west of MHZ showing FL360 squawking XYZA.  At first I suspected it was a false target (ring-around) from a radar site; and did a flight plan readout on the code.  The code belonged to Aircraft X who was at FL360; established well outside ZME in ZHU airspace and heading away toward AEX/IAH.  If the target had disappeared after a couple hits; we may have thought little of it.  The target was moving rapidly northeast bound toward MEM; exhibiting a greater airspeed than Aircraft X; and showing good steady radar identification for approximately 35 miles; I was on the D-side; so I'm not sure; but I would estimate the target marched along for about 35 or 40 miles and then disappeared.  During this time; I stood up to view the underlying sector 45 and sector 66 for any possible targets in the same vicinity; but there were none; there was an aircraft just southeast of the target at FL380 and my R-side asked him if he showed anything on his TCAS; the pilot replied negative.  Sector 43 is routinely our busiest sector; if this had happened during a busy session it would have created much confusion and some panic.The target vector was not relative to Aircraft X [and] any radar site; in an example of the old ring-around scenario; Aircraft X would have been 30 SW of the radar site and the false target 30 N of the site; then 30 NNE; 30NE; etc. I do not know where the ADSB antennas are; but if one is near VKS then it may have an impact on the situation.  I think it's important to note that the false target was not moving opposite Aircraft X; it was not a mirror presentation; but I would estimate 150 degrees opposite.  We told the ASIC (Area Supervisor In Charge) when [ASIC] returned to the area and took down information and reported it to someone.  I have not seen this type of event before; and have no idea what caused it.

Callback: Controller advised that this is an ongoing problem that has not been fixed. Reporter stated the technicians are seeing that it is along the same route from Vicksburg; MS to Memphis; TN. According to the reporter; the facility has not found out what is causing the problem but are still investigating.



Synopsis: ZME Controller reports of a Mode-C intruder target moving NE towards their airspace at a fast rate. Controllers checked with pilots in the vicinity to see if they saw it on TCAS and they did not. Controller referenced it to something like ring-around but said it was not because the targets did not correlate to ring-around. Controller reported the incident to Front Line Manager (FLM).