Date: 201403
Local time of day: 1201-1800
Location: IWA.Airport, AZ
Flight conditions: VMC
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Initial Approach
Airspace: Class E P50
ATC / advisory: TRACON P50
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Other / Unknown
Anomaly: Conflict NMAC
Detector: Automation Aircraft RA; Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Airspace Structure; Human Factors; Procedure
Primary problem: Ambiguous

Narrative: Arrival to IWA was via the HUUTY1 RNAV arrival. ATIS was advising visuals to Runway 30L. When our flight checked on with Phoenix Approach we requested vectors for the RNAV 30L Approach. We were conducting initial OE and I intended to conduct the RNAV approach to satisfy a training requirement. After checking in we were immediately given a level off; slowed; and then vectored by ATC for spacing with traffic. It eventually became apparent that; based on our handling; we were being vectored for the visual approach. At this point I queried ATC about our request for the RNAV approach and was told we would be unable to conduct the approach and to expect the visual for 30L. Our flight was then assigned a heading of 120 and descended to 5;000 FT; putting us on an extended downwind for 30L; northeast of the airport. Approximately 12 miles from the airport we were given a heading of 210 and then cleared for the visual approach to Runway 30L. Our flight began a descent from 5;000 FT at this time. As we rolled out on a heading of 210 I immediately became aware of a TCAS target within 5 miles of our position at our 12 o'clock. TCAS indicated that it was 300 FT below our altitude. At the time I became aware of the traffic I assumed control of the aircraft from the OE candidate and immediately leveled the aircraft. At this point we received a TCAS RA to descend; followed immediately by a climb RA. At our nearest point of closure I noted the TCAS showed traffic 100 FT below our altitude. I was never able to visually identify the traffic but noted that it appeared at our 11-12 o'clock position on the TCAS. After we cleared the traffic conflict I advised ATC that we had maneuvered for a TCAS RA and requested that a 'near midair collision report' be filed. At no time did ATC advise us of traffic in our immediate vicinity. The flight continued without further incident. After completing the flight I contacted the Dispatch Supervisor on duty; and gave her my report for NTSB notification and advised her that I had requested the near midair collision report with ATC. I then followed up with the Duty Pilot to insure I satisfied all the requirements for reporting the incident. Are the separation requirements when being handled on a visual approach; as opposed to an IAP; different?  Are we conducting visual approaches at our own risk?  While I did not visually confirm the traffic I did note that the conflict was in close proximity to the Aerobatic box frequented by the Air Combat operators at IWA. ATC never advised us why he could not allow us to complete the RNAV approach. It's my hope that it was not to relieve himself of the responsibility to providing appropriate separation services.




Synopsis: Air Carrier Captain experiences a NMAC during a visual approach to Runway 30L at IWA.