Narrative:

I was working the local control 2 position, controling aircraft using runway 21R and in and out of class D airspace from the west. Aircraft X was doing pattern operations on runway 21R. They requested a full stop landing. Since aircraft X parks southeast of runway 21L, I handed the aircraft X off to the local-1 controller. Approximately 2 mi southwest of the airport is a house whose resident complaints when aircraft overfly her house. To avoid the house, aircraft Y flew a wide pattern. I was listening as the local-1 controller was talking to the 2 aircraft. When the local-1 controller told aircraft Y to enter a wide downwind, I looked towards aircraft X. I then observed aircraft Y pass in front of aircraft X. They were so close I thought they were going to hit. After they passed, I pointed out aircraft Y to the local-1 controller. Aircraft Y was reporting a standard pattern entry, and the aircraft is based here. The only way any of us in the tower could have helped aircraft X is with a tower radar display. Supplemental information from acn 469744: one aircraft was entering pattern while the other aircraft was changing from one runway to the other from the pattern altitude prior to landing on parallel runway. The near miss occurred as one aircraft was turning from crosswind to downwind while the other aircraft was about to turn from the 45 degree entry to left downwind. Contributing factors were pilots not expecting traffic at the point of contact and the use of 2 radio frequencys just prior to incident. Callback conversation with reporter acn 469483 revealed the following information: reporter said he did not know the outcome of the near midair collision. He believed it was still under investigation by the FSDO. He did not add any additional information.

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Original NASA ASRS Text

Title: 2 GA ACFT AT PRC HAVE NMAC DURING PATTERN ENTRY.

Narrative: I WAS WORKING THE LCL CTL 2 POS, CTLING ACFT USING RWY 21R AND IN AND OUT OF CLASS D AIRSPACE FROM THE W. ACFT X WAS DOING PATTERN OPS ON RWY 21R. THEY REQUESTED A FULL STOP LNDG. SINCE ACFT X PARKS SE OF RWY 21L, I HANDED THE ACFT X OFF TO THE LCL-1 CTLR. APPROX 2 MI SW OF THE ARPT IS A HOUSE WHOSE RESIDENT COMPLAINTS WHEN ACFT OVERFLY HER HOUSE. TO AVOID THE HOUSE, ACFT Y FLEW A WIDE PATTERN. I WAS LISTENING AS THE LCL-1 CTLR WAS TALKING TO THE 2 ACFT. WHEN THE LCL-1 CTLR TOLD ACFT Y TO ENTER A WIDE DOWNWIND, I LOOKED TOWARDS ACFT X. I THEN OBSERVED ACFT Y PASS IN FRONT OF ACFT X. THEY WERE SO CLOSE I THOUGHT THEY WERE GOING TO HIT. AFTER THEY PASSED, I POINTED OUT ACFT Y TO THE LCL-1 CTLR. ACFT Y WAS RPTING A STANDARD PATTERN ENTRY, AND THE ACFT IS BASED HERE. THE ONLY WAY ANY OF US IN THE TWR COULD HAVE HELPED ACFT X IS WITH A TWR RADAR DISPLAY. SUPPLEMENTAL INFO FROM ACN 469744: ONE ACFT WAS ENTERING PATTERN WHILE THE OTHER ACFT WAS CHANGING FROM ONE RWY TO THE OTHER FROM THE PATTERN ALT PRIOR TO LNDG ON PARALLEL RWY. THE NEAR MISS OCCURRED AS ONE ACFT WAS TURNING FROM XWIND TO DOWNWIND WHILE THE OTHER ACFT WAS ABOUT TO TURN FROM THE 45 DEG ENTRY TO L DOWNWIND. CONTRIBUTING FACTORS WERE PLTS NOT EXPECTING TFC AT THE POINT OF CONTACT AND THE USE OF 2 RADIO FREQS JUST PRIOR TO INCIDENT. CALLBACK CONVERSATION WITH RPTR ACN 469483 REVEALED THE FOLLOWING INFO: RPTR SAID HE DID NOT KNOW THE OUTCOME OF THE NMAC. HE BELIEVED IT WAS STILL UNDER INVESTIGATION BY THE FSDO. HE DID NOT ADD ANY ADDITIONAL INFO.

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.