Narrative:

I entered downwind for runway 9 at gxy; from a 45 degree entry. I was showing landing lights and wingtip strobes and the red anti-collision beacon. I announced my position on the 45 degree entry and immediately after turning onto the downwind leg. Moments later; as I was crossing runway 34; a skylane flew directly in front of me and above me; approximately 20 ft horizontally and 5 ft vertically. Although I had looked toward the approach to runway 34; I did not see any aircraft. Although many aircraft were in the pattern for runway 9; because the wind was favoring runway 9; and I heard all of them announce their position as did I; I did not hear him on the radio at all until moments after the near collision; when I heard 'greeley traffic; I am departing the pattern to the north.' I could see aircraft X flying north at my same altitude. I do not know why I did not see him before the event because I looked to the south where it should have been. I do not know if he was showing landing lights or not. The WX was clear and sunny with a few clouds. I am assuming that he was on a practice approach on the ILS to runway 34 and did his missed. He did not appear to be climbing when I saw him; however. In any event; aircraft X flew through a very active pattern. There is some dispute whether the tpa at gxy is 800 ft or 1000 ft AGL. Most GA aircraft there use 800 ft AGL; as did I. In any event; he was either at the approximately tpa being used by everyone that day; or was about 190-195 ft below the 'official' 1000 ft tpa. Either way; it was a dangerous maneuver. I recommend that practice ILS approachs be prohibited whenever runway 9/27 is the favored and active runway.

Google
 

Original NASA ASRS Text

Title: A C172 IN THE TRAFFIC PATTERN AT AN UNCONTROLLED FIELD HAS A NMAC WITH A C182.

Narrative: I ENTERED DOWNWIND FOR RWY 9 AT GXY; FROM A 45 DEG ENTRY. I WAS SHOWING LNDG LIGHTS AND WINGTIP STROBES AND THE RED ANTI-COLLISION BEACON. I ANNOUNCED MY POS ON THE 45 DEG ENTRY AND IMMEDIATELY AFTER TURNING ONTO THE DOWNWIND LEG. MOMENTS LATER; AS I WAS XING RWY 34; A SKYLANE FLEW DIRECTLY IN FRONT OF ME AND ABOVE ME; APPROX 20 FT HORIZLY AND 5 FT VERTICALLY. ALTHOUGH I HAD LOOKED TOWARD THE APCH TO RWY 34; I DID NOT SEE ANY ACFT. ALTHOUGH MANY ACFT WERE IN THE PATTERN FOR RWY 9; BECAUSE THE WIND WAS FAVORING RWY 9; AND I HEARD ALL OF THEM ANNOUNCE THEIR POS AS DID I; I DID NOT HEAR HIM ON THE RADIO AT ALL UNTIL MOMENTS AFTER THE NEAR COLLISION; WHEN I HEARD 'GREELEY TFC; I AM DEPARTING THE PATTERN TO THE N.' I COULD SEE ACFT X FLYING N AT MY SAME ALT. I DO NOT KNOW WHY I DID NOT SEE HIM BEFORE THE EVENT BECAUSE I LOOKED TO THE S WHERE IT SHOULD HAVE BEEN. I DO NOT KNOW IF HE WAS SHOWING LNDG LIGHTS OR NOT. THE WX WAS CLR AND SUNNY WITH A FEW CLOUDS. I AM ASSUMING THAT HE WAS ON A PRACTICE APCH ON THE ILS TO RWY 34 AND DID HIS MISSED. HE DID NOT APPEAR TO BE CLBING WHEN I SAW HIM; HOWEVER. IN ANY EVENT; ACFT X FLEW THROUGH A VERY ACTIVE PATTERN. THERE IS SOME DISPUTE WHETHER THE TPA AT GXY IS 800 FT OR 1000 FT AGL. MOST GA ACFT THERE USE 800 FT AGL; AS DID I. IN ANY EVENT; HE WAS EITHER AT THE APPROX TPA BEING USED BY EVERYONE THAT DAY; OR WAS ABOUT 190-195 FT BELOW THE 'OFFICIAL' 1000 FT TPA. EITHER WAY; IT WAS A DANGEROUS MANEUVER. I RECOMMEND THAT PRACTICE ILS APCHS BE PROHIBITED WHENEVER RWY 9/27 IS THE FAVORED AND ACTIVE RWY.

Data retrieved from NASA's ASRS site as of January 2009 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.