Narrative:

On mar/fri/95 at approximately XA00 local, the following situation took place: I had been orbiting the field at dupage county airport, west chicago, il for 40 mins at 2500 ft MSL having received approval to do so from the tower and having received a squawk code. During that 40 mins period I was given several TA's and heard the tower advise several other planes of my position. At about XB00 pm local as I was moving from east to west, approximately 1 mi north of the tower (I was circling with left turns) I dropped the right wing slightly and saw a window full of blue and white highwing single engine aircraft. I immediately pushed the yoke forward feeling there was no way we would not collide. I leveled at 2000 ft MSL and turned enough to see the aforementioned plane proceeding southeast. The pilot of that plane called the tower and reported nearly hitting 'a low wing plane.' the tower responded they had been trying to contact him with a TA and that he had not replied. He made no further comment. I made no comment to the tower at this time. However, I do not recall hearing them attempting to contact anyone who did not respond immediately preceding this occurrence, and I know they did not attempt to advise me of the approaching traffic. I continued to circle for another 20 mins before landing. My purpose for this flight was to break in cylinders after a top overhaul -- which is the reason I remained in the vicinity of the airport for an extended period of time.

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Original NASA ASRS Text

Title: NMAC. ACFT ORBITING ARPT UNDER TWR CTL ALMOST HAD MIDAIR BECAUSE TFC NOT RPTED BY TWR.

Narrative: ON MAR/FRI/95 AT APPROX XA00 LCL, THE FOLLOWING SIT TOOK PLACE: I HAD BEEN ORBITING THE FIELD AT DUPAGE COUNTY ARPT, W CHICAGO, IL FOR 40 MINS AT 2500 FT MSL HAVING RECEIVED APPROVAL TO DO SO FROM THE TWR AND HAVING RECEIVED A SQUAWK CODE. DURING THAT 40 MINS PERIOD I WAS GIVEN SEVERAL TA'S AND HEARD THE TWR ADVISE SEVERAL OTHER PLANES OF MY POS. AT ABOUT XB00 PM LCL AS I WAS MOVING FROM E TO W, APPROX 1 MI N OF THE TWR (I WAS CIRCLING WITH L TURNS) I DROPPED THE R WING SLIGHTLY AND SAW A WINDOW FULL OF BLUE AND WHITE HIGHWING SINGLE ENG ACFT. I IMMEDIATELY PUSHED THE YOKE FORWARD FEELING THERE WAS NO WAY WE WOULD NOT COLLIDE. I LEVELED AT 2000 FT MSL AND TURNED ENOUGH TO SEE THE AFOREMENTIONED PLANE PROCEEDING SE. THE PLT OF THAT PLANE CALLED THE TWR AND RPTED NEARLY HITTING 'A LOW WING PLANE.' THE TWR RESPONDED THEY HAD BEEN TRYING TO CONTACT HIM WITH A TA AND THAT HE HAD NOT REPLIED. HE MADE NO FURTHER COMMENT. I MADE NO COMMENT TO THE TWR AT THIS TIME. HOWEVER, I DO NOT RECALL HEARING THEM ATTEMPTING TO CONTACT ANYONE WHO DID NOT RESPOND IMMEDIATELY PRECEDING THIS OCCURRENCE, AND I KNOW THEY DID NOT ATTEMPT TO ADVISE ME OF THE APCHING TFC. I CONTINUED TO CIRCLE FOR ANOTHER 20 MINS BEFORE LNDG. MY PURPOSE FOR THIS FLT WAS TO BREAK IN CYLINDERS AFTER A TOP OVERHAUL -- WHICH IS THE REASON I REMAINED IN THE VICINITY OF THE ARPT FOR AN EXTENDED PERIOD OF TIME.

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.