Narrative:

I was flying as pilot in command from the right seat; with another pilot in the left seat. We were coming back from the local practice area after practicing lazy 8's and were in ZZZ's delta airspace by this point. After requesting to stay in the pattern for some performance landing practice; tower asked us to switch frequency. This frequency is usually used when the tower is busy and needs a separate frequency for traffic in the pattern. We were instructed to make straight in for runway xxl; and I complied. I was lined up on centerline on an extended final when tower asked me if I was lined up for xxl. I told them I was. Looking back on this; I believe this may be because the traffic we nearly collided with was to our left and I assume they were cleared for xxr.after tower asked to clarify my position; I noticed on the G430W traffic display that traffic [was] very quickly approaching in a descent from above and our back left. As the traffic gets closer to us I pull carburetor and throttle; descending to get out of the way. I asked tower if they had the location of the traffic above us; and if they were speaking with this traffic. To my recollection all tower had to say regarding my second question was something like 'no; they are not on my frequency.' I assumed that meant the traffic was on the normal tower frequency.for about 30 seconds the traffic appeared to be exactly on top of us and at an altitude anywhere from zero to three hundred feet above us; continuing the descent with us. After a brief level off of a couple of seconds to reassess where the traffic was and to consider the terrain below me; the other pilot told me to continue my descent because the traffic was still very close to us. The traffic passed off of our right side and lined up for xxr. They [were] only a couple of hundred feet from us to our 2 o'clock. Once we had traffic in sight we discontinued the rate of our descent and initiated a go-around because of the un-stabilized approach we made. The other pilot landed the plane. We decided to make the landing a full-stop and terminate the rest of the practice because we were shaken up.I am not sure how much I descended or how fast. I did not receive a terrain warning on my G430 but we were under the glide slope as indicated by the PAPI's. Also of note; the traffic was a low wing airplane and we are a high wing; making it hard to see each other. I believe the controller needed to do a better job verifying the other pilot was talking to tower; and in initiating traffic-avoiding instructions to us both. When tower uses two separate frequencies for the parallel runways; it should be instructed [for] the pilots to monitor both.

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Original NASA ASRS Text

Title: Two C172 pilots reported a near midair collision with another aircraft while on approach to a tower controlled airport.

Narrative: I was flying as pilot in command from the right seat; with another pilot in the left seat. We were coming back from the local practice area after practicing Lazy 8's and were in ZZZ's Delta airspace by this point. After requesting to stay in the pattern for some performance landing practice; Tower asked us to switch frequency. This frequency is usually used when the Tower is busy and needs a separate frequency for traffic in the pattern. We were instructed to make straight in for Runway XXL; and I complied. I was lined up on centerline on an extended final when Tower asked me if I was lined up for XXL. I told them I was. Looking back on this; I believe this may be because the traffic we nearly collided with was to our left and I assume they were cleared for XXR.After Tower asked to clarify my position; I noticed on the G430W traffic display that traffic [was] very quickly approaching in a descent from above and our back left. As the traffic gets closer to us I pull carburetor and throttle; descending to get out of the way. I asked Tower if they had the location of the traffic above us; and if they were speaking with this traffic. To my recollection all Tower had to say regarding my second question was something like 'No; they are not on my frequency.' I assumed that meant the traffic was on the normal Tower frequency.For about 30 seconds the traffic appeared to be exactly on top of us and at an altitude anywhere from zero to three hundred feet above us; continuing the descent with us. After a brief level off of a couple of seconds to reassess where the traffic was and to consider the terrain below me; the other pilot told me to continue my descent because the traffic was still very close to us. The traffic passed off of our right side and lined up for XXR. They [were] only a couple of hundred feet from us to our 2 o'clock. Once we had traffic in sight we discontinued the rate of our descent and initiated a go-around because of the un-stabilized approach we made. The other pilot landed the plane. We decided to make the landing a full-stop and terminate the rest of the practice because we were shaken up.I am not sure how much I descended or how fast. I did not receive a terrain warning on my G430 but we were under the glide slope as indicated by the PAPI's. Also of note; the traffic was a low wing airplane and we are a high wing; making it hard to see each other. I believe the controller needed to do a better job verifying the other pilot was talking to Tower; and in initiating traffic-avoiding instructions to us both. When Tower uses two separate frequencies for the parallel runways; it should be instructed [for] the pilots to monitor both.

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.