Narrative:

The event described below was a near mid-air collision. The event took place directly over the tracy airport (tcy). I was nearing the end of a VFR cross-country trip to livermore (lvk). Tracy was my final waypoint before livermore. I was the third aircraft in a group. All three aircraft were in communication on 122.75. Rain showers had moved into the area and we decided to overfly tracy; listen to the livermore ATIS and make a decision at that time whether to land at tracy or proceed to livermore. I overflew tracy at 2;500 ft. When I crossed runway 26/8 on a northerly heading I noticed a 4 place cessna (probably 172 or 182) at my 2 o'clock position approximately 100 ft higher and 400 ft to the east and on runway 26 heading. The cessna appeared to be climbing. I initiated a steep descent to 1;500 ft. I do not believe that I would have collided with the cessna if I had not made the descent...the descent was precautionary. I suspect the cessna was executing a practice missed approach based on its position; altitude and climbing attitude. However; if the cessna was in communication with ATC they would have been informed of my position because my transponder was on. Following the incident I proceeded to livermore and landed behind the two aircraft in the group I had been following.circumstances: a number of factors contributed to my failure to see the converging aircraft until we were in close proximity. 1) it was the end of a long flight and I was tired. 2) I was distracted by preparations to land at livermore. 3) I was concerned weather at livermore might be marginal (rain and low visibility) although ATIS was reporting good weather (winds 2907: visibility 10 miles; sky 9;500 overcast). 4) I was in communication with the group (two other aircraft) I was flying with and not monitoring ATC or tracy CTAF. 5) my visual scan was focused on the second aircraft in our group I was following.

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Original NASA ASRS Text

Title: Decathlon pilot experienced a NMAC with a Cessna while over flying TCY airport at 2;500 FT.

Narrative: The event described below was a near mid-air collision. The event took place directly over the Tracy airport (TCY). I was nearing the end of a VFR cross-country trip to Livermore (LVK). Tracy was my final waypoint before Livermore. I was the third aircraft in a group. All three aircraft were in communication on 122.75. Rain showers had moved into the area and we decided to overfly Tracy; listen to the Livermore ATIS and make a decision at that time whether to land at Tracy or proceed to Livermore. I overflew Tracy at 2;500 FT. When I crossed Runway 26/8 on a northerly heading I noticed a 4 place Cessna (probably 172 or 182) at my 2 o'clock position approximately 100 FT higher and 400 FT to the east and on Runway 26 heading. The Cessna appeared to be climbing. I initiated a steep descent to 1;500 FT. I do not believe that I would have collided with the Cessna if I had not made the descent...the descent was precautionary. I suspect the Cessna was executing a practice missed approach based on its position; altitude and climbing attitude. However; if the Cessna was in communication with ATC they would have been informed of my position because my transponder was on. Following the incident I proceeded to Livermore and landed behind the two aircraft in the group I had been following.Circumstances: A number of factors contributed to my failure to see the converging aircraft until we were in close proximity. 1) It was the end of a long flight and I was tired. 2) I was distracted by preparations to land at Livermore. 3) I was concerned weather at Livermore might be marginal (rain and low visibility) although ATIS was reporting good weather (winds 2907: visibility 10 miles; Sky 9;500 overcast). 4) I was in communication with the group (two other aircraft) I was flying with and not monitoring ATC or Tracy CTAF. 5) My visual scan was focused on the second aircraft in our group I was following.

Data retrieved from NASA's ASRS site as of April 2012 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.