SR20 flight instructor reported an near midair collision while operating in the pattern at a non-tow...

Narrative:

While on midfield downwind on left traffic for runway xx with the student pilot at the controls; I; the instructor; realize of a traffic coming from the west slightly higher than traffic pattern altitude descending and heading towards our airplane. I announce 'I have control' and I commence a pitch down to avoid otherwise an impact from the other airplane. The traffic never appeared on tcad [traffic collision avoidance device] and I presumably did not have an operational transponder since the flight was not tracked by any software. After evasive action; the traffic joins the downwind very close to us while I am inquiring in frequency to attempt to communicate with that traffic. I established communication with the traffic and I arrange the sequence for the arrival to the runway ahead of that traffic.

Original NASA ASRS Text

Title: SR20 flight instructor reported an NMAC while operating in the pattern at a non-towered airport.

Narrative: While on midfield downwind on left traffic for Runway XX with the Student Pilot at the controls; I; the Instructor; realize of a traffic coming from the west slightly higher than traffic pattern altitude descending and heading towards our airplane. I announce 'I have control' and I commence a pitch down to avoid otherwise an impact from the other airplane. The traffic never appeared on TCAD [Traffic Collision Avoidance Device] and I presumably did not have an operational transponder since the flight was not tracked by any software. After evasive action; the traffic joins the downwind very close to us while I am inquiring in frequency to attempt to communicate with that traffic. I established communication with the traffic and I arrange the sequence for the arrival to the runway ahead of that traffic.

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.

Attributes
ACN	1602491
Time
Date	201812
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	SR20
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Flight Plan	None
Person 1
Function	Instructor Pilot Flying
Qualification	Flight Crew Flight Instructor Flight Crew Commercial
Events
Anomaly	Conflict NMAC Deviation - Procedural Published Material / Policy

SR20 flight instructor reported an near midair collision while operating in the pattern at a non-towered airport.