Flight Instructor reported a NMAC event during downwind leg while on a training flight. The Instructor saw the non-reporting intruder aircraft turning an early crosswind on a collision course which prompted the Instructor to take evasive action.
Synopsis
Flight Instructor reported a NMAC event during downwind leg while on a training flight. The Instructor saw the non-reporting intruder aircraft turning an early crosswind on a collision course which prompted the Instructor to take evasive action.
Narrative
I was doing pattern work with a student and we had just rolled wings level on the downwind leg when we saw Aircraft Y rapidly approaching us from the crosswind leg. He had done a touch and go behind us without making any radio calls so we were not aware he was there and was following us on the upwind leg. He turned crosswind earlier and lower than he should have which put him on a collision course from beneath our left wing where we could not see him. We saw him when he came in view at our 10 o'clock forward of our wing and he was climbing right into us as he began turning downwind. I estimate he was around 100-200 ft. from us at this point. We immediately did a right 360 and let him continue on the downwind leg ahead of us. Solution 1: Make radio calls on every leg at an uncontrolled airport. He was not making radio calls on his upwind and crosswind legs (it is possible we missed the transmissions but do not recall hearing any radio calls). Solution 2: Aircraft in the pattern need to wait to turn crosswind until 300 ft. below TPA like recommended in AC 90-66C paragraph 11.7. This could have mitigated this problem by preventing him from turning crosswind so soon and also putting him higher on the crosswind leg giving us a better chance of spotting him in a low wing airplane.Solution 3: Use ADS-B in for traffic advisories. After speaking with the Chief CFI from the school of the conflict aircraft it was determined that this student was on a solo flight and those students rarely use ADS-B in for traffic awareness. I think this is a must; especially when flying on a nice morning at a busy uncontrolled airport.
Second reporter narrative
In ZZZ airport I was in traffic pattern and I missed the traffic coming to left downwind Runway XX. I turned downwind too early. I got flight and ground training about radio communication and uncontrolled air space procedure.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.