PA-28R Cherokee Arrow All Series
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 221.4; Flight Crew Total 9355.7; Flight Crew Type 400
Situational Awareness; Communication Breakdown
Conflict NMAC
Flight Crew Took Evasive Action
Airport; Chart Or Publication; Human Factors
Aircraft X; was conducting a touch-and-go landing; following a practice VOR/DME approach to RWY 15; at ZZZ.  Aircraft Y; was holding short; awaiting our touch-and-go landing. During the touch-and-go; the Student Pilot was flying the airplane; when the CFI observed Aircraft Z on short final to RWY 33.  No radio transmission was heard by either the touch-and-go traffic or the airplane holding short of RWY 15. The CFI immediately took control of the airplane; took off; and maneuvered to avoid a mid-air collision with the Aircraft Z; which proceeded to land on RWY 33. Moments later; the pilot of Aircraft Z radioed and informed; via CTAF; he had been on the incorrect frequency; thus; not permitting aircraft on the ground or in the pattern to realize his proximity to the airfield.Based on all accounts; the aircraft on short final to RWY 33 did not see the airplane on the touch-and-go. Had the CFI of Aircraft X not taken immediate action to maneuver his airplane out of the approach and landing path of Aircraft Z; there is a high likelihood the two aircraft would have collided. Approximate distance between the two airplanes was within 300 feet laterally and 100 feet vertically.
I was in route from ZZZ1 to ZZZ2 when I chose to divert to ZZZ for three reasons. One; there was coastal fog or low ceilings being reported near ZZZ2. Two; I was having multiple gauge issues including a malfunctioning suction system; and three my EGT Gauge also had stopped working. I knew the mechanic at ZZZ and thought it was prudent to pay him a visit. I canceled my flight following and tuned to the wrong local frequency I announced my position multiple times approaching ZZZ and heard nothing at the other end of the radio because I was unknowingly on the wrong frequency.  I knew the wind was calm and I fixated on the runway numbers 33. I didn't see the other airplane in the pattern in the opposite direction. It wasn't until my wheels were just touching the ground when I realized there was another plane doing a touch and go in the opposite direction of the runway. The safest thing for me to do was stay on the ground and I was left of the runway strips so moved to the far left of the runway while applying heavy brakes while the other plane was departing approximately 100+ AGL and to my right at the other side of the 100 ft. wide runway.I immediately exited the runway and tuned to the appropriate local frequency and sincerely apologized for being on the wrong frequency. Being a new private pilot I am learning many lessons. I believe I was distracted by the malfunctioning gauges and diversion to an unfamiliar airport. I fixated on the runway instead of looking closely for traffic and double checking my eerily silent radio frequency. If I had taken the time to check all available information about the airport this could have been avoided. Despite what is going on in the cockpit this close call reinforced the importance of always looking and scanning out the window. This is a reminder that when I become task saturated I can easily miss an important step like the correct radio frequency. Moving forward in my flying career I feel like I will be a much safer pilot with the lessons learned and this day will always be a reminder to never repeat these multiple mistakes.
Pilots reported incorrect radio frequency selected resulted in a Near Mid Air Collision.