Pilots reported incorrect radio frequency selected resulted in a near mid air collision.

Attributes
ACN	1662069
Time
Date	201907
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	PA-28R Cherokee Arrow All Series
Operating Under FAR Part	Part 91
Flight Phase	Takeoff
Route In Use	None
Flight Plan	VFR
Aircraft 2
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Taxi
Component
Aircraft Component	Vacuum System
Person 1
Function	Pilot Flying
Qualification	Flight Crew Commercial Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 221.4 Flight Crew Total 9355.7 Flight Crew Type 400
Person 2
Function	Single Pilot Captain Pilot Flying
Qualification	Flight Crew Private
Experience	Flight Crew Last 90 Days 43.9 Flight Crew Total 133.7 Flight Crew Type 133.7
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 300 Vertical 100

Narrative:

Aircraft X; was conducting a touch-and-go landing; following a practice VOR/DME approach to runway 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 runway 33. No radio transmission was heard by either the touch-and-go traffic or the airplane holding short of runway 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 runway 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 runway 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.

Original NASA ASRS Text

Title: Pilots reported incorrect radio frequency selected resulted in a Near Mid Air Collision.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.