Communication Breakdown
Conflict NMAC
Flight Crew Took Evasive Action
Airport; Human Factors
While entering left downwind on a 45 entry for Runway 05 at CGZ we almost collided with a high wing Cessna. We had been making radio calls 10 miles out; 5 miles out; 3 mile 45; and entering downwind. While merging in the downwind I (the instructor pilot sitting right seat) looked left one last time and noticed the Cessna climbing above us. I reduced power and kept the Cessna insight; discontinued the traffic pattern. I had attempted multiple radio calls to 'Cessna in the downwind' with no response. Eventually I heard 'Skylane XYZ; radio check.' I confirmed that Skylane XYZ was the aircraft involved in the NMAC and he admitted that he was having radio problems; not able to communicate very well. The G430 had no traffic information on it as we were not in radar contact. Look outside more and do not fly CGZ on heavy traffic days.
PA28 instructor pilot entering the CGZ traffic pattern on the 45 reports a NMAC with a C182 climbing on the downwind. CTAF procedures were in use by the instructor but no reports were received from the C182; whose pilot latter admitted to having radio difficulties.