Date: 202107
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Skyhawk 172/Cutlass 172
Operator: Other Flight School
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Landing
Airspace: Class G ZZZ
Second aircraft: Skyhawk 172/Cutlass 172
Aircraft component: VHF
Component problem: Malfunctioning
Reporter organization: Corporate
Reporter function: Pilot Flying; Instructor
Reporter qualification: Flight Crew Multiengine; Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Human factors: Troubleshooting; Situational Awareness; Distraction; Confusion; Communication Breakdown
Anomaly: Aircraft Equipment Problem Less Severe; Conflict NMAC; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Airspace Structure; Human Factors; Aircraft; Procedure
Primary problem: Procedure

Narrative: I was flying with a private pilot student to practice landings at ZZZ1. We departed ZZZ; and arrived midfield at ZZZ1 at XA:40 local time according to my ADSB track log. Other traffic in the pattern was using Runway XX; so we made right traffic for XX. The student and I completed two laps in the traffic pattern for XX. On our third lap in the pattern; we were flying in front of another Skyhawk in the pattern; Aircraft Y. At XA:57 we turned base to final for runway 26 and made a radio call on CTAF. We heard Aircraft Y call base behind us. At XA:58; just past the numbers of Runway XX; I saw Aircraft Z low and climbing towards us. I could see his tail number. I called my controls and executed a go around and a turn to the right. I attempted to raise Aircraft Z on the radio; but had no answer. Aircraft Y responded to my calls and advised me that the aircraft appeared to be making a left crosswind turn and exiting the pattern to the north. I attempted to raise the pilot on 1XX.X; in case he maybe just had the frequency wrong; but this did not work to raise a response. My student and I exited the traffic pattern to the north to gain altitude. Then; re entered right traffic for [Runway] XX with a 45 degree entry to the downwind. We continued to make our radio calls for the traffic pattern. As we turned base for XX; I observed on my ADSB that Aircraft Z had made a 180 degree turn from his heading and was now headed directly for us; 300 feet high and descending. I took the controls and called a go around; extending the base. The aircraft was now at my altitude; close and lining up for the base to final for Runway XX. I had not heard any radio calls from the aircraft. We exited the ZZZ1 area and departed to another area until we could contact approach to get clearance back in to ZZZ for a landing. After the incident; I called the pilot of Aircraft Y to confirm what had happened. The pilot mentioned that they had landed at ZZZ1 and talked to a mechanic who witnessed the incident and talked to Aircraft Z after he had landed. According to the mechanic; the pilot of Aircraft Z said that they had a radio failure. It is unknown to me what transpired with the aircraft after that.




Synopsis: Instructor reported two Near Mid Air Collisions with the same aircraft that was having communications problems and attempting to land.