Flight Crew Private
Flight Crew Last 90 Days 4; Flight Crew Total 301; Flight Crew Type 42
Situational Awareness; Communication Breakdown
Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Procedure; Human Factors
Busy day at the airport in the ZZZ traffic pattern. I heard a slightly garbled message about a Piper Cub entering a tear drop for the 45 to Runway XX as I was turning crosswind. I continued looking for the cub but did not see it and made my downwind turn and radio call. About halfway through downwind TCAS alerted me that there was something closer than a mile about 300 feet below me even though I was at TPA (Traffic Pattern Altitude). Worried I was over top of another aircraft I turned left and then right aggressively to check under the wings and nose for an aircraft and I did not see anything. Passed the numbers on downwind and started my descent to base. Called my base turn; heard something garbled. Then heard someone calling 'the Diamond' to which the pilot said I had gotten within 100 yards of him and that I should watch for traffic better. I did look; I had been in the pattern practicing all morning; I made clearing maneuvers to make sure there was nothing in a blind spot but at the end of the day I did not see him. While radios are not required; he obviously had one. Some of the hardest things to see while in the air are airports and other planes. It also would have been beneficial had the Piper Cub been at published TPA and even though not required; when within a very busy non towered airport; clearly announcing his position.
Pilot reported communication issues caused a Near Mid Air Collision at a non-towered airport.