Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 150; Flight Crew Total 805; Flight Crew Type 775
Communication Breakdown; Situational Awareness
Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Took Evasive Action
Human Factors
I was doing an instrument approach in to CVO with a student. RNAV 35. We had made normal radio calls; 10; 7; 5; 2 and 2 miles out.There was one plane in the downwind who had called #2; landing behind my student and I on Runway 35. When we were below the LPV minimums and the student had removed the foggles; somebody on the ground holding short of Runway 35 called out 'there is about to be a mid air collision for the 2 planes on final.'My student and I both were looking out straight ahead and to the sides and saw nothing. Out of nowhere a plane [Aircraft Y] came over the top of us; from behind and to our right and almost clipped our left wingtip.To our knowledge; there was only one plane in the downwind aside from us on short final and 2 planes holding short of 35 ready to depart. My student confirms that they saw Aircraft Y land on Runway 35 and taxi off with no radio calls.We did everything right; making all the appropriate radio calls. Aircraft Y made no calls and we never saw them on ADS-B or out the window. The pilots from on the ground from two different planes both confirmed that Aircraft Y made no radio calls and that I and my student were doing everything correctly.I never saw Aircraft Y visually or over ADS-B. The student was under the foggles for the approach but when he went visual; we still never saw a plane near us.I can confirm nobody was departing Runway 17 at the time because there was already 1 plane doing pattern work for 35; and the plane who called out the near midair collision from the ground; had just completed a taxi from 17 to 35 on the ground because it was the runway in use.This was within feet of hitting our wing from above. Not only was this incredibly unsafe; but the fact that no radio call was made ever is even more concerning.
GA flight instructor reported an NMAC during final approach to CVO non-towered airport.  Reporter stated the other aircraft never made any radio calls during the approach which contributed to the event.