Date: 202001
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Skyhawk 172/Cutlass 172
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Training
Flight phase: Landing
Airspace: Class G ZZZ
ATC / advisory: CTAF ZZZ
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: FBO
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Student
Human factors: Communication Breakdown
Second reporter function: Instructor; Pilot Not Flying
Anomaly: Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: I was approaching ZZZ at approximately XA:00 for pattern work. About 9 to 10 miles out; I made my first radio call to state my intentions before entering the pattern. 'ZZZ airport traffic; Cessna X plane inbound 10 miles out; ZZZ airport traffic.' There was no radio communication from any other pilots; so I proceeded to enter left pattern on the downwind for Runway XX. On downwind; I made another radio call. 'ZZZ airport traffic; Cessna X on Downwind for Runway XX.' As I was turning left on base and notice incoming traffic at my 1 o'clock at the same altitude and coming in for the same runway. There wasn't no radio calls from the pilot coming from the east nor did they state their intention for ZZZ airport. Both planes were within 50 to 100 feet of each other.


Second narrative: My student was conducting his first solo flight for private pilot at ZZZ (Non-towered airport). After ensuring student was confident in the airport environment with flight and communications he was endorsed and permitted to conduct his solo. As observed from the ground; student took off and entered the left hand traffic pattern for Runway XX. While approaching the downwind to base leg I observed a second aircraft later observed to be a Cessna 172 enter a long straight-in final for Runway XX from the East. At that time student turned onto his base leg with no indication that either aircraft were aware of the others presence. Unable to observe from the ground actual altitudes and distance I observed student turn final for Runway XX with still no action from the approaching inbound aircraft from the East. The inbound aircraft from the East still continued the approach and began flying under student both approaching short final. What was estimated to be approximately 50 feet apart vertically student's aircraft orientation did not present he was aware of the second aircraft under him. Estimating to be approximately 400 feet AGL the lower aircraft made a level right turn to the North avoiding the incident and rejoined the pattern accordingly to land. Student made a full stop taxi back to myself at which time I advised him of the situation and took immediate corrective training action. Student advised me he made all of the call outs he was trained to do for the airport and at no time did he hear radio communications from the second aircraft. He also advised he did not observe the inbound aircraft from the East while conducting his scans. I was unable to have radio communications at the time as a portable radio was not available and being inside the FBO would require negative visual contact with the soloing student. The next day at approximately XA:30 EST I spoke with the instructor who was in the second aircraft with her student. She advised she too was under VFR conditions after being released from an IFR flight plan and was flying the RNAV XX approach. She observed my student in the pattern but was unable to make radio contact. She also stated she attempted again to make contact from the FBO with negative contact. Both myself and the other instructor agreed on see and avoid procedures at non towered airports and would train the students accordingly from this event.


Synopsis: C172 student pilot and instructor reported an NMAC at a non-towered airport.