Skyhawk 172/Cutlass 172
Flight Crew Commercial; Flight Crew Flight Instructor
Flight Crew Last 90 Days 200; Flight Crew Total 2000; Flight Crew Type 1900
Distraction; Communication Breakdown; Situational Awareness; Training / Qualification
Conflict NMAC
Flight Crew Took Evasive Action
ATC Equipment / Nav Facility / Buildings; Human Factors; Procedure
While descending into ZZZ; my student elected to make a midfield entry into the downwind. We briefed the approach and announced our position on CTAF at about 4 miles outside of the airport. Following our call; another aircraft asked our location in relation to the airport. We attempted to reply; but severe radio congestion prevented a response. The student and I began scanning for traffic; but it appeared that no other aircraft were in our area. Just after crossing midfield; we began our turn to downwind when the previous aircraft announced a midfield downwind. We spotted the traffic 100 to 150 feet below us and passing underneath us to our left. We took evasive action and initiated a climb; then rejoined a normal downwind behind the aircraft. No evasive action was taken by the other aircraft and it seemed he was not aware of the near miss. The rest of the flight occurred without incident.I believe the cause of the near miss was a result of extreme frequency congestion in the area. Communication in the area was encumbered by heavy usage and several radio calls we made were blocked due to other transmissions; leading to confusion over aircraft positions at the airport we were using. A review of the chart showed a large number of airports with 50NM operating on XYY.Z and several of those airports were surrounding the busy nearby metro areas. My recommendation would be to evaluate the airport usage of that area and assign unique frequencies several busier airports in the area.
An instructor pilot reported as the student entered the downwind at a non-towered airport they had an NMAC with another aircraft entering the pattern. The reporter also reported excessive radio congestion on the CTAF frequency due to numerous airports in the vicinity sharing the same frequency.