Narrative:

Flying the jacobs 2 arrival into phoenix gateway; phoenix approach assigned us swirl intersection at 11;000 ft and 250 KT. We were in managed descent on profile passing thru about 12;500 ft and received a TA; within a few seconds a C-130 appeared out of the haze coming towards us from our 10 to 11 o'clock. After just a couple seconds of analyzing the closure rate and position it became frighteningly clear that evasive action was required immediately. I disconnected the autopilot; arrested our descent and started to climb. The C-130 passed directly below us; approximately 400-500 ft. We then rejoined our vertical path; made the crossing restriction and called ATC. ATC said they had seen the primary target but 'didn't report it because all VFR traffic is supposed to be below 3;500 ft in that area'.smoke from wildfires reducing visibility on a VFR day; VFR traffic flying thru an IFR arrival with no mode C reporting and no report from ATC of primary radar target. Suggestions: better ATC handling while on IFR flight plan and mode C requirement for aircraft flying around IFR routes.

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Original NASA ASRS Text

Title: A319 First Officer reported an NMAC with a C130 in the vicinity of IWA.

Narrative: Flying the Jacobs 2 arrival into Phoenix Gateway; Phoenix Approach assigned us SWIRL Intersection at 11;000 FT and 250 KT. We were in managed descent on profile passing thru about 12;500 FT and received a TA; within a few seconds a C-130 appeared out of the haze coming towards us from our 10 to 11 o'clock. After just a couple seconds of analyzing the closure rate and position it became frighteningly clear that evasive action was required immediately. I disconnected the autopilot; arrested our descent and started to climb. The C-130 passed directly below us; approximately 400-500 FT. We then rejoined our vertical path; made the crossing restriction and called ATC. ATC said they had seen the primary target but 'didn't report it because all VFR traffic is supposed to be below 3;500 FT in that area'.Smoke from wildfires reducing visibility on a VFR day; VFR traffic flying thru an IFR arrival with no Mode C reporting and no report from ATC of primary radar target. Suggestions: Better ATC handling while on IFR flight plan and Mode C requirement for aircraft flying around IFR routes.

Data retrieved from NASA's ASRS site as of July 2013 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.