Narrative:

I was giving tail wheel instruction for the purpose of the trainee working towards a tail wheel endorsement. The traffic pattern was very busy for both runways at dvt and we had made several landings all as touch and goes. We were operating off the north runway landing and departing from 7L. After several landings I took control of the aircraft on the runway and made the take off with the intent of demonstrating another pattern and wheel landing to my student. I was seated on the right side and our patterns were left traffic each time for 7L. As we lifted off the runway; tower instructed us that traffic was inbound from northeast of the field and told us to extend our upwind until we had him in sight. The student; who is an ATP; spotted the traffic to our left; entering the downwind; and told me I was clear to start the crosswind turn. I could not see the traffic myself; due to the climb angle and being seated on the right side. As I rolled out on crosswind the tower said to turn back to the right due to the traffic ahead. I rolled back to the upwind. Again my student called out the traffic and said we would be good to turn. We notified tower and were cleared to turn while maintaining our own separation. Once again I began a turn to the crosswind and the tower again told us to turn back to the upwind for traffic ahead. As I turned back to the upwind again; we spotted the aircraft ahead and going below us and realized we had been looking at a 3rd aircraft on the downwind. Tower commented that traffic had gone right below us and told us to turn crosswind at our discretion and follow the traffic for landing. Tower did not say anything else and we made a number of other landings before finishing the instructional flight. Several things were factors in this event. First was my over reliance on the student; who is very experienced and is someone I fly with a lot. Also; the position of the aircraft made it such that I could not see it myself during climb out from the right seat. In addition; the pattern and the frequency were extremely busy. Also; each time we would fly the pattern the number of aircraft in the pattern would change; from 1 or 2 to 3 or 4. This was a recipe for spotting the wrong airplane and getting out of sequence. Also; I am not sure the tower ever told us there was another aircraft already on downwind; but this would have helped us to know we had another aircraft that would be sequenced between us that we needed to be looking for. Due to the downwind aircraft being close to the direction of our traffic when we were told to follow; we were led into the trap of spotting the wrong airplane.this incident reminds me on how careful we have to be about relying on another pilot when spotting traffic. I am also reminded of how careful we have to be with multiple aircraft in the pattern; in order to not get out of sequence and to always ask if unsure.

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Original NASA ASRS Text

Title: C170 Instructor with student experienced an NMAC in the traffic pattern at DVT after being told to extend upwind for traffic. When the traffic was sighted and the crosswind turn initiated the Tower advised to turn back to the upwind for additional traffic. The process is repeated and resulted in an NMAC with a third aircraft in the pattern.

Narrative: I was giving tail wheel instruction for the purpose of the trainee working towards a tail wheel endorsement. The traffic pattern was very busy for both runways at DVT and we had made several landings all as touch and goes. We were operating off the north runway landing and departing from 7L. After several landings I took control of the aircraft on the runway and made the take off with the intent of demonstrating another pattern and wheel landing to my student. I was seated on the right side and our patterns were left traffic each time for 7L. As we lifted off the runway; tower instructed us that traffic was inbound from northeast of the field and told us to extend our upwind until we had him in sight. The student; who is an ATP; spotted the traffic to our left; entering the downwind; and told me I was clear to start the crosswind turn. I could not see the traffic myself; due to the climb angle and being seated on the right side. As I rolled out on crosswind the tower said to turn back to the right due to the traffic ahead. I rolled back to the upwind. Again my student called out the traffic and said we would be good to turn. We notified tower and were cleared to turn while maintaining our own separation. Once again I began a turn to the crosswind and the tower again told us to turn back to the upwind for traffic ahead. As I turned back to the upwind again; we spotted the aircraft ahead and going below us and realized we had been looking at a 3rd aircraft on the downwind. Tower commented that traffic had gone right below us and told us to turn crosswind at our discretion and follow the traffic for landing. Tower did not say anything else and we made a number of other landings before finishing the instructional flight. Several things were factors in this event. First was my over reliance on the student; who is very experienced and is someone I fly with a lot. Also; the position of the aircraft made it such that I could not see it myself during climb out from the right seat. In addition; the pattern and the frequency were extremely busy. Also; each time we would fly the pattern the number of aircraft in the pattern would change; from 1 or 2 to 3 or 4. This was a recipe for spotting the wrong airplane and getting out of sequence. Also; I am not sure the tower ever told us there was another aircraft already on downwind; but this would have helped us to know we had another aircraft that would be sequenced between us that we needed to be looking for. Due to the downwind aircraft being close to the direction of our traffic when we were told to follow; we were led into the trap of spotting the wrong airplane.This incident reminds me on how careful we have to be about relying on another pilot when spotting traffic. I am also reminded of how careful we have to be with multiple aircraft in the pattern; in order to not get out of sequence and to always ask if unsure.

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.