Date: 201704
Local time of day: 1801-2400
Location: UMP.Airport, IN
Flight conditions: VMC
Weather elements / visibility: Haze / Smoke; 10
Light: Dusk
Aircraft: Cessna Single Piston Undifferentiated or Other Model
Operator: FBO
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Initial Climb
Airspace: Class G UMP
ATC / advisory: CTAF UMP
Second aircraft: Cessna Single Piston Undifferentiated or Other Model
Reporter organization: FBO
Reporter function: Pilot Not Flying; Instructor
Reporter qualification: Flight Crew Commercial; Flight Crew Instrument; Flight Crew Flight Instructor
Human factors: Situational Awareness; Communication Breakdown
Anomaly: Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: Flight was a short and soft field takeoff and landing practice with a student that is nearly finished with his private pilot certification. We were holding short for 2 announced planes in the pattern and were maintaining visual contact with them. After the second plane cleared the runway; we taxied onto the active runway. Both the student and I remember looking down final to check for other aircraft. I definitely try to instill this into my students to avoid situations like this one and was shocked that it happened to us. The student started our takeoff roll and just as we left the ground we noticed another Cessna that was unannounced on the CTAF fly over us just upwind of the runway with approximately 400 ft vertical separation. He had obviously initiated an immediate go-around due to our takeoff roll. We were able to continue our climb out almost as normal with a slight offset to the downwind side; although we were both concerned about wake turbulence since there was a crosswind. However; we did not encounter any.Both the student and I were surprised we did not see him on final. The Cessna that we made go-around continued a fairly tight pattern and landed without any radio communications on the CTAF and taxied to the FBO ramp. We had continued in the pattern and were on short final as the Cessna requested a radio check from the ramp. I replied 'now we hear you' and he then apologized for being on the wrong frequency; I apologized for not seeing him. He claimed to have been high but that his landing light was on. The previous two aircraft that landed before him were much more noticeable due to their landing lights being on against the high overcast layer and near sunset time. Both the student and I believe we would have seen his landing light if it he was on a normal final when we had pulled onto the runway.I feel the factors the contributed to us not seeing the other Cessna are as follows:1. Lack of radio cues to look for aircraft. However; it is an uncontrolled field so it is still solely our responsibility in this case to see and avoid. I do not fault the pilot of the other aircraft. Given enough time every one will encounter a no radio aircraft; especially at a non-tower field.2. High overcast layer with near sunset lighting while looking southeasterly down final did not provide a much contrast to spot the aircraft.3. A high base/final leg by the other aircraft resulting an angle hard to see from our aircraft.




Synopsis: Cessna flight instructor reported a NMAC on takeoff from UMP with another aircraft that was on a high approach which had to perform a go-around. The other aircraft was on the wrong frequency.