Narrative:

Weather was VFR severe clear; pilots had been reporting the airport 20 miles out for the visual approach. A PA32 requested a no gyro ASR approach. I know from experience that ASR (airport surveillance radar) approaches are time consuming; especially no-gyro ASR's. I worked to prepare my other traffic so I could devote more attention to the ASR. I gave the PA32 vector to the runway 28 final and began no gyro vectors near the final. I was in the process of giving the PA32 the information; MDA and other information. The ASR to runway 28 has a step down approach procedure; 900 till 3 NM final and then 400 with a missed approach point 1 NM final. I was concentrating on giving all the information correctly but I also descended (gave the pilot the MDA) of the PA32 early which conflicts with the MVA. The low altitude alert went off. Other controllers commented I was slow to respond since I did not think that the aircraft was in proximity to even warrant an alert. I realized later that switching between scopes to my right my perceived mileage even though it was monitoring it was incorrect. I thought the PA32 was near enough to the fix; descent to the MDA should have started and continued with the approach. An unexpected VFR helicopter passed through the flight path of the PA32 and I did issue that traffic. The local controller had told me about traffic I just did not expect traffic to pass in front of my aircraft. The approach continued with the PA32 centered with the runway on the final. I did not get the pilots intentions for a touch and go until very late in the approach. The PA32 did a touch and go as a B737 departed before this aircraft. A cautionary wake turbulence call was probably necessary. I did not feel as confident working this approach as I use to feel when I worked them all the time. I generally work only about one a year for real; and not via simulator. I was not certain on how to phrase the step down MDA so the pilot knew the information. Give the ASR approach duties to a stand alone position. Prepare completely make necessary calls to tower about the approach to runway 28 sooner. Ask pilot for his intentions and give tower the information. Issue low altitude alerts. My actions for this situation were clumsy and slow. I am capable of much better.

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Original NASA ASRS Text

Title: TRACON Controller described the issuance of a 'no gyro' ASR Approach; noting his/her unfamiliarity with the procedure and failure to complete some required actions.

Narrative: Weather was VFR severe clear; pilots had been reporting the airport 20 miles out for the visual approach. A PA32 requested a no gyro ASR Approach. I know from experience that ASR (Airport Surveillance Radar) Approaches are time consuming; especially no-gyro ASR's. I worked to prepare my other traffic so I could devote more attention to the ASR. I gave the PA32 vector to the Runway 28 final and began no gyro vectors near the final. I was in the process of giving the PA32 the information; MDA and other information. The ASR to Runway 28 has a step down approach procedure; 900 till 3 NM final and then 400 with a missed approach point 1 NM final. I was concentrating on giving all the information correctly but I also descended (gave the pilot the MDA) of the PA32 early which conflicts with the MVA. The Low Altitude Alert went off. Other controllers commented I was slow to respond since I did not think that the aircraft was in proximity to even warrant an alert. I realized later that switching between scopes to my right my perceived mileage even though it was monitoring it was incorrect. I thought the PA32 was near enough to the fix; descent to the MDA should have started and continued with the approach. An unexpected VFR helicopter passed through the flight path of the PA32 and I did issue that traffic. The Local Controller had told me about traffic I just did not expect traffic to pass in front of my aircraft. The approach continued with the PA32 centered with the runway on the final. I did not get the pilots intentions for a touch and go until very late in the approach. The PA32 did a touch and go as a B737 departed before this aircraft. A cautionary wake turbulence call was probably necessary. I did not feel as confident working this approach as I use to feel when I worked them all the time. I generally work only about one a year for REAL; and not via simulator. I was not certain on how to phrase the step down MDA so the pilot knew the information. Give the ASR Approach duties to a stand alone position. Prepare completely make necessary calls to tower about the approach to Runway 28 sooner. Ask pilot for his intentions and give tower the information. Issue Low Altitude Alerts. My actions for this situation were clumsy and slow. I am capable of much better.

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.