Narrative:

I was working all sectors combined; traffic volume and complexity was low. Aircraft Y conducting para jumps over mzj at 10;000 ft. Aircraft X inbound from the northwest of mzj level at 11;000 ft to pass safely above the jump zone. Jumps commenced southwest of mzj without incident and aircraft Y descended; when leaving approximately 4;300 ft radar service was terminated and the data tag was put in track suspend because they were making multiple jumps. The data tag dropped off the scope around 3;300 ft and I assumed aircraft Y landed at mzj until the suspended target acquired approximately 10 miles southeast of mzj near avq airport. The suspended target dropped off and acquired a few times near avq and since it was a suspended data tag there was no altitude readout displayed. Aircraft X was on a 100 degree heading to intercept the TACAN final RY12 dma level at 5;000 ft when the collision alert sounded. I immediately issued a traffic alert to aircraft X on the VFR target (who was aircraft Y; the aircraft terminated 10-15 miles west near mzj). At the time of the traffic alert; I was unable to immediately assess whether the VFR target was climbing; level; descending; etc. So initially I did not recommend an alternate course of action for aircraft X. After watching the replay the VFR target; (aircraft Y) had conducted a high speed low passes over avq and was in a hard left turn and climbing rapidly directly at aircraft X. Aircraft X responded to the TCAS RA; he had to descend rapidly and turn to avoid collision. After aircraft X returned to his previously issued heading and altitude; I called out in the blind to see if aircraft Y was monitoring my frequency; which he was and I questioned why he was so far from mzj and conducting abrupt maneuvers in that area. The pilot said he was setting up for an approach at mzj. Aircraft X completed the approach and I was relieved from position. On climb-out after the TACAN approach aircraft X requested a full stop and advised the controller they would be filing a near midair collision report. The only thing that would have helped me assess the situation earlier and issue the traffic earlier; which may or may not have prevented this situation because of the abrupt maneuvers conducted by aircraft Y; would be an altitude readout on the suspended data tag. Once the data tag is suspended; there is no information displayed. I feel it could have possibly helped me to make a decision sooner.

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Original NASA ASRS Text

Title: Tucson TRACON (U90) Controller reported of a near-mid-air-collision due to an aircraft making abrupt maneuvers. The aircraft in question had a suspended transponder and did not show an altitude. Pilot of normal aircraft reported of NMAC to another Controller.

Narrative: I was working all sectors combined; traffic volume and complexity was low. Aircraft Y conducting PARA jumps over MZJ at 10;000 ft. Aircraft X inbound from the NW of MZJ level at 11;000 ft to pass safely above the jump zone. Jumps commenced SW of MZJ without incident and Aircraft Y descended; when leaving approximately 4;300 ft radar service was terminated and the data tag was put in track suspend because they were making multiple jumps. The data tag dropped off the scope around 3;300 ft and I assumed Aircraft Y landed at MZJ until the suspended target acquired approximately 10 miles SE of MZJ near AVQ airport. The suspended target dropped off and acquired a few times near AVQ and since it was a suspended data tag there was no altitude readout displayed. Aircraft X was on a 100 degree heading to intercept the TACAN final RY12 DMA level at 5;000 ft when the collision alert sounded. I immediately issued a traffic alert to Aircraft X on the VFR target (who was Aircraft Y; the aircraft terminated 10-15 miles west near MZJ). At the time of the traffic alert; I was unable to immediately assess whether the VFR target was climbing; level; descending; etc. so initially I did not recommend an alternate course of action for Aircraft X. After watching the replay the VFR target; (Aircraft Y) had conducted a high speed low passes over AVQ and was in a hard left turn and climbing rapidly directly at Aircraft X. Aircraft X responded to the TCAS RA; he had to descend rapidly and turn to avoid collision. After Aircraft X returned to his previously issued heading and altitude; I called out in the blind to see if Aircraft Y was monitoring my frequency; which he was and I questioned why he was so far from MZJ and conducting abrupt maneuvers in that area. The pilot said he was setting up for an approach at MZJ. Aircraft X completed the approach and I was relieved from position. On climb-out after the TACAN approach Aircraft X requested a full stop and advised the controller they would be filing a NMAC report. The only thing that would have helped me assess the situation earlier and issue the traffic earlier; which may or may not have prevented this situation because of the abrupt maneuvers conducted by Aircraft Y; would be an altitude readout on the suspended data tag. Once the data tag is suspended; there is no information displayed. I feel it could have possibly helped me to make a decision sooner.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.