Date: 202005
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Small Aircraft
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Landing
Airspace: Class G ZZZ
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Personal
Reporter function: Pilot Not Flying; Instructor
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Human factors: Situational Awareness; Communication Breakdown
Anomaly: Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: While on a routine FAR part 91 training flight; my student and I were conducting practice landings and remained in the traffic pattern as announced. We had discussed prior to takeoff the importance in non-tower controlled airspace and the importance of vigilance and that we'd make additional radio calls to announce both our position and intentions. In addition; given the student's prior training and holder of a private pilot license; student added the importance of situational awareness of other traffic. We also discussed the importance to observe both the 12 O'clock and final approach area during the base leg due to the close alignment of the parallel runways at our airport.As we turned from downwind to base; I reiterated to observe the area ahead as well as the final approach area for traffic. Just prior to turning base to final I observed a plane that appeared to be at our 12 O'clock flight for the parallel runway somewhat higher than our altitude. I suddenly realized that the oncoming plane had overshot his turn and instead began a turn to final and aligned with our runway slightly above and ahead of use. I asked the student to execute a go-around so as not to [get] caught in the wake of the encroaching aircraft as at this time it was now ahead and descending for landing our intended runway. We executed the go-around; and re-entered the traffic pattern for a landing. While in the downwind I called the local FBO and asked that they get the tail number for the aircraft that had just landed and asked that the pilot remain at the FBO until my arrival. Upon landing I proceeded to the FBO where I met the pilot as he deplaned. I inquired whether he was aware of his action and he indicated he decided to use the longer of the two runways as he was high and fast; and that he never saw our aircraft. I then inquired at the frequency he was on and he indicated he had requested the UNICOM frequency from ATC and was given XYY.ZA. I indicated to him that the Tower closes at XA00 and the CTAF was the same as the Tower frequency XYB.C...he apologized; but I indicated that in light of the fact he never saw our aircraft that his actions had caused an unsafe near miss and that he should be aware that his actions were not only careless but placed safety and risk to others due to his carelessness. The take away from this event is that because of recent changes in ATC and Tower closures due to the recent cut-backs and pandemic has created unusual risk to safety due partly because of failure by novice pilot's complacency and lack of experience and non-standard practices. I suggest as a benefit to others to be vigilant in their situational awareness and review basic operating procedures.




Synopsis: Instructor pilot reported an airborne conflict with an aircraft that was not on correct frequency.