Narrative:

Training in the traffic pattern at home airport. Our aircraft was not equipped with radio. There had been several aircraft coming in and out of the traffic pattern and we were doing touch-and-goes. We were following one aircraft and were on base leg just starting our turn to final when we saw a piper cherokee on final just below us and to our right. I took control of the aircraft and flew over the arriving cherokee and continued around the pattern to the right of the runway. I thought we had been doing a good job of looking for other aircraft but I missed this one. He did not maneuver or go around and I do not know if he saw us or not. Obviously the primary cause was us not seeing the other aircraft. Contributing factors are the very large patterns flown by many of the aircraft arriving at this field. Since I did not see the other aircraft I do not know how he entered the pattern. Uncontrolled fields require extra vigilance. Flight instruction adds some distraction and the instructor must be very careful to make sure that all traffic is spotted especially in the traffic pattern.

Google
 

Original NASA ASRS Text

Title: J3 EXPERIENCES NMAC WITH PA28 IN TRAFFIC PATTERN.

Narrative: TRAINING IN THE TFC PATTERN AT HOME ARPT. OUR ACFT WAS NOT EQUIPPED WITH RADIO. THERE HAD BEEN SEVERAL ACFT COMING IN AND OUT OF THE TFC PATTERN AND WE WERE DOING TOUCH-AND-GOES. WE WERE FOLLOWING ONE ACFT AND WERE ON BASE LEG JUST STARTING OUR TURN TO FINAL WHEN WE SAW A PIPER CHEROKEE ON FINAL JUST BELOW US AND TO OUR R. I TOOK CTL OF THE ACFT AND FLEW OVER THE ARRIVING CHEROKEE AND CONTINUED AROUND THE PATTERN TO THE R OF THE RWY. I THOUGHT WE HAD BEEN DOING A GOOD JOB OF LOOKING FOR OTHER ACFT BUT I MISSED THIS ONE. HE DID NOT MANEUVER OR GO AROUND AND I DO NOT KNOW IF HE SAW US OR NOT. OBVIOUSLY THE PRIMARY CAUSE WAS US NOT SEEING THE OTHER ACFT. CONTRIBUTING FACTORS ARE THE VERY LARGE PATTERNS FLOWN BY MANY OF THE ACFT ARRIVING AT THIS FIELD. SINCE I DID NOT SEE THE OTHER ACFT I DO NOT KNOW HOW HE ENTERED THE PATTERN. UNCTLED FIELDS REQUIRE EXTRA VIGILANCE. FLT INSTRUCTION ADDS SOME DISTR AND THE INSTRUCTOR MUST BE VERY CAREFUL TO MAKE SURE THAT ALL TFC IS SPOTTED ESPECIALLY IN THE TFC PATTERN.

Data retrieved from NASA's ASRS site as of May 2009 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.