Narrative:

#2 aircraft cherokee low wing fixed. I monitored unicom and heard #2 pilot announcing locations and intentions. I broadcast 'crossing north to south, midfield at 8500 ft, descending to pattern altitude for 45 degree entry for left traffic runway 24 payson.' the other pilot requested my location. I advised '1/2 mi north of runway -- I have your aircraft upwind runway 24.' I crossed the runway and must have begun my descent and I saw the other aircraft wing up crosswind to downwind. At approximately 1/2 mi south of the runway I saw the other aircraft at my altitude wide on downwind. I immediately dropped the nose and slipped aggressively. The other aircraft passed overhead approximately 300 ft. I resumed level flight and noted that I was at approximately 6100 ft. The other pilot asked my location and I advised 'off your wing.' other pilot 'are you under me?' I advised that I was turning to a 45 degree downwind entry. Both planes then landed uneventfully -- no discussion. Just prior to beginning my approach to payson, I had overheard an altimeter setting and wind information. I did not check my altimeter on landing at payson but did so at taylor and it was accurate within -75 ft without adjustment. I do not fault the other pilot although she may have been high and wide (tpa shows 6200 ft). I must have began descent and done so at a high rate before crossing the downwind pattern. I feel that had I not been able to take evasive action or had not observed the other traffic in my scan we would have collided.

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Original NASA ASRS Text

Title: PLT OF SMA RPTS NMAC WITH SECOND SMA WHEN ENTERING TFC PATTERN AT UNCTLED ARPT.

Narrative: #2 ACFT CHEROKEE LOW WING FIXED. I MONITORED UNICOM AND HEARD #2 PLT ANNOUNCING LOCATIONS AND INTENTIONS. I BROADCAST 'XING N TO S, MIDFIELD AT 8500 FT, DSNDING TO PATTERN ALT FOR 45 DEG ENTRY FOR L TFC RWY 24 PAYSON.' THE OTHER PLT REQUESTED MY LOCATION. I ADVISED '1/2 MI N OF RWY -- I HAVE YOUR ACFT UPWIND RWY 24.' I CROSSED THE RWY AND MUST HAVE BEGUN MY DSCNT AND I SAW THE OTHER ACFT WING UP XWIND TO DOWNWIND. AT APPROX 1/2 MI S OF THE RWY I SAW THE OTHER ACFT AT MY ALT WIDE ON DOWNWIND. I IMMEDIATELY DROPPED THE NOSE AND SLIPPED AGGRESSIVELY. THE OTHER ACFT PASSED OVERHEAD APPROX 300 FT. I RESUMED LEVEL FLT AND NOTED THAT I WAS AT APPROX 6100 FT. THE OTHER PLT ASKED MY LOCATION AND I ADVISED 'OFF YOUR WING.' OTHER PLT 'ARE YOU UNDER ME?' I ADVISED THAT I WAS TURNING TO A 45 DEG DOWNWIND ENTRY. BOTH PLANES THEN LANDED UNEVENTFULLY -- NO DISCUSSION. JUST PRIOR TO BEGINNING MY APCH TO PAYSON, I HAD OVERHEARD AN ALTIMETER SETTING AND WIND INFO. I DID NOT CHK MY ALTIMETER ON LNDG AT PAYSON BUT DID SO AT TAYLOR AND IT WAS ACCURATE WITHIN -75 FT WITHOUT ADJUSTMENT. I DO NOT FAULT THE OTHER PLT ALTHOUGH SHE MAY HAVE BEEN HIGH AND WIDE (TPA SHOWS 6200 FT). I MUST HAVE BEGAN DSCNT AND DONE SO AT A HIGH RATE BEFORE XING THE DOWNWIND PATTERN. I FEEL THAT HAD I NOT BEEN ABLE TO TAKE EVASIVE ACTION OR HAD NOT OBSERVED THE OTHER TFC IN MY SCAN WE WOULD HAVE COLLIDED.

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.