Citation V/Ultra/Encore (C560)
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 19.0
Distraction; Confusion; Situational Awareness; Communication Breakdown
ATC Issue All Types; Aircraft Equipment Problem Less Severe; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem
Airspace Structure; Aircraft; Human Factors
Aircraft X called asking for a deviation due to weather. I did not have a data block for Aircraft X in my airspace. I asked the aircraft's position. He stated a distance near a VOR. I searched my southern boundary and did not see any aircraft displaying 34;000 feet. or the squawk code associated with the aircraft. I called the adjacent Center and they also looked for Aircraft X and said they had no display.I tried to locate the aircraft via looking for a primary target which did not work; and bearings from [surrounding VORS]. This allowed me to have a general position of the aircraft knowing [their] flight plan route and taking [into] account they may have deviated due to their request at first contact. I called for help from a Supervisor. He plugged in the D Side as the volume for the sector was increasing. I continued to work the sector while advising the Supervisor and D-Side of the issue with Aircraft X. I asked D-Side to create another flight plan for Aircraft X with a new squawk code. He made a duplicate flight plan with [a] new call sign. I asked the aircraft to Ident and reset his transponder to the new code. [There was still no] Mode C or Primary target displayed.[I] told [the] pilot we had no radar information on his plane and asked him to recycle his transponder. He said he was going to his second transponder and that still did not work. After getting a position report I made the decision to descend the aircraft out of RVSM airspace and put him on a Non Radar route. Once [the] aircraft was near 28;000 feet a primary target showed up in the reported range from [a VOR] near the boundary with [another] sector. The D-side coordinated the aircraft information with [the other] sector who now displayed a primary target. [The] aircraft was switched to [that] sector.[I am] not sure what led to the event. I turned all information over to Supervision.
Center Controller reported an aircraft was deviating for weather and their transponder failed causing ATC to lose track of the aircraft's position.