Narrative:

I was in the pattern for runway 17R at apa airport practicing touch-and-goes. Numerous other aircraft, mostly cessnas, joined and left the pattern during this period. While on upwind after a touch-and-go, I heard the tower controller instruct a cessna to begin his crosswind turn, as there was traffic behind him. At this point, I believed that there was only one other aircraft in the pattern for runway 17R, and that the 'traffic' in question was me. Due to the steep climb angle of the S-2B, my forward visibility was extremely limited, and I was reluctant to perform s-turns due to the close proximity of runway 17L on my left side and potential traffic on downwinds on my right side (r-hand traffic was in use for runway 17R). I observed a cessna passing my 3 O'clock position on its downwind leg as I reached 1200 ft AGL on the upwind leg. I leveled off at 7000 ft MSL (1200 ft AGL) and continued to fly upwind for another 10-15 seconds to allow adequate spacing behind the slower cessna. I then turned crosswind, and a few seconds later the tower controller advised that I had cut off my cessna traffic, and asked if I had that traffic in sight. After a brief scan out the left side of the canopy, I replied that I did not have the traffic in sight and asked the controller what he wanted me to do. He replied that I should continue to fly wbound. I did so, and went to full throttle in order to clear the conflict area more quickly. A second or 2 later, I spotted the cessna traffic at approximately my 9:30 O'clock position, perhaps 150 ft lower. I applied a 3G 'pull' on the stick, and the cessna passed well below and behind me. Contributing factors: loss of situational awareness as various aircraft joined and left the traffic pattern. Limited visibility in the S-2B during climb. Performance mismatch between the pitts and the cessnas. Lack of room for s-turns.

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Original NASA ASRS Text

Title: A PITTS S-2B IN THE TFC PATTERN AT APA HAD AN NMAC WITH A CESSNA.

Narrative: I WAS IN THE PATTERN FOR RWY 17R AT APA ARPT PRACTICING TOUCH-AND-GOES. NUMEROUS OTHER ACFT, MOSTLY CESSNAS, JOINED AND LEFT THE PATTERN DURING THIS PERIOD. WHILE ON UPWIND AFTER A TOUCH-AND-GO, I HEARD THE TWR CTLR INSTRUCT A CESSNA TO BEGIN HIS XWIND TURN, AS THERE WAS TFC BEHIND HIM. AT THIS POINT, I BELIEVED THAT THERE WAS ONLY ONE OTHER ACFT IN THE PATTERN FOR RWY 17R, AND THAT THE 'TFC' IN QUESTION WAS ME. DUE TO THE STEEP CLB ANGLE OF THE S-2B, MY FORWARD VISIBILITY WAS EXTREMELY LIMITED, AND I WAS RELUCTANT TO PERFORM S-TURNS DUE TO THE CLOSE PROX OF RWY 17L ON MY L SIDE AND POTENTIAL TFC ON DOWNWINDS ON MY R SIDE (R-HAND TFC WAS IN USE FOR RWY 17R). I OBSERVED A CESSNA PASSING MY 3 O'CLOCK POS ON ITS DOWNWIND LEG AS I REACHED 1200 FT AGL ON THE UPWIND LEG. I LEVELED OFF AT 7000 FT MSL (1200 FT AGL) AND CONTINUED TO FLY UPWIND FOR ANOTHER 10-15 SECONDS TO ALLOW ADEQUATE SPACING BEHIND THE SLOWER CESSNA. I THEN TURNED XWIND, AND A FEW SECONDS LATER THE TWR CTLR ADVISED THAT I HAD CUT OFF MY CESSNA TFC, AND ASKED IF I HAD THAT TFC IN SIGHT. AFTER A BRIEF SCAN OUT THE L SIDE OF THE CANOPY, I REPLIED THAT I DID NOT HAVE THE TFC IN SIGHT AND ASKED THE CTLR WHAT HE WANTED ME TO DO. HE REPLIED THAT I SHOULD CONTINUE TO FLY WBOUND. I DID SO, AND WENT TO FULL THROTTLE IN ORDER TO CLR THE CONFLICT AREA MORE QUICKLY. A SECOND OR 2 LATER, I SPOTTED THE CESSNA TFC AT APPROX MY 9:30 O'CLOCK POS, PERHAPS 150 FT LOWER. I APPLIED A 3G 'PULL' ON THE STICK, AND THE CESSNA PASSED WELL BELOW AND BEHIND ME. CONTRIBUTING FACTORS: LOSS OF SITUATIONAL AWARENESS AS VARIOUS ACFT JOINED AND LEFT THE TFC PATTERN. LIMITED VISIBILITY IN THE S-2B DURING CLB. PERFORMANCE MISMATCH BTWN THE PITTS AND THE CESSNAS. LACK OF ROOM FOR S-TURNS.

Data retrieved from NASA's ASRS site as of July 2007 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.