Date: 201903
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Skyhawk 172/Cutlass 172
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Initial Approach
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Second aircraft: Mooney Aircraft Undifferentiated or Other Model
Reporter organization: Personal
Reporter function: Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Commercial
Human factors: Human-Machine Interface; Situational Awareness
Second reporter function: Pilot Not Flying
Anomaly: ATC Issue All Types; Conflict NMAC
Detector: Automation Aircraft TA; Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors
Primary problem: Human Factors

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.


Second narrative: Myself (Instrument Rated SEL Pilot) and the Pilot Flying (Commercial Rated SEL Pilot) were on approach to Runway XXL at ZZZ. The pilot flying was in the right seat and I was monitoring from the left seat. (Note this aircraft does not require 2 flight crewmembers; however; since we were both practicing maneuvers; 2 of us were there).We were directed by Tower to tune to a separate frequency typically used for aircraft doing pattern work on Runway XXL. The Tower queried us on whether we were lined up for XXL; which we replied in the affirmative. Shortly after; I noticed another aircraft on our G430W traffic advisory system quickly approaching from approximately our 7 o'clock position. This aircraft was initially indicating approximately 300 feet above our present altitude and descending. We queried the Tower whether or not they were talking to this aircraft; and the controller responded that she wasn't; but the controller on the main Tower frequency was; and apparently the traffic was landing on the parallel Runway XXR.The traffic advisory showed our aircraft converging at approximately the same altitude; and we immediately took action to descend because this traffic was descending faster and was essentially on top of us. The Mooney (we believe this was a Mooney) is a low wing aircraft; and the C172 is a high wing aircraft; making it exceptionally difficult to see one another. Eventually; after descending well below the glide slope on final; we saw the Mooney approximately 250 feet horizontally and 100 feet above us at our 2 o'clock position. The pilot flying in our C172 continued the approach and performed a go-around maneuver due to our approach at this point being unstabilized. I then took over the aircraft and performed a normal pattern and approach to a full stop landing. We decided to discontinue at that time due to being somewhat 'shaken-up' over the incident.I believe the controller we were talking to may have been relatively new and it was fairly busy on Local Control at the time; but either ourselves or the Mooney should have been given instructions to de-conflict the potential collision on the approach. ZZZ Class Delta airspace can get relatively busy; and when the pattern frequency is separated; both controllers on Local need to coordinate to avoid conflicts such as this. A phone call was made to the Tower explaining our encounter approximately 20 minutes after the event occurred.


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