Narrative:

This morning I departed S27 flew over the nearby mountains and returned across 'lower valley' toward S27; slowing descending to pattern altitude of 3;800 MSL. Approximately four to five miles southeast of S27; I heard an aircraft calling kalispell city; 'five to the west;' altitude unknown. I then reported my position; 'three to four to the southeast; over the river; inbound for landing; will be entering a left downwind for runway 13.' at this time a third aircraft reported 'inbound for landing; will keep an eye out for you once I find him.' my course was a forty five degree intercept to left downwind; as reported; and offered a geographic reference as well; 'over the river.' I then reported to both aircraft that I was entering a left downwind for 13; and was nearly to the radio towers southeast of the field. Suddenly my passenger and I noted a red and white aircraft climbing; banking toward us; and taking evasive maneuvers with a turn to the pilot's right. I immediately banked right as well; passing perhaps within 300 ft horizontally of this third aircraft. Based on my position reports; it remains unclear to me why he was in this area; seemingly flying the pattern backward and/or on an intercept to inbound standard left pattern traffic. Now established on the left downwind for 13; I noted the sock was slightly favoring 31. I reported this; and indicated I would be crossing midfield to enter a left downwind for 31. The initial pilot was in sight; and he was in a more favorable position to land first. As such; we both communicated; and I indicated I would land 'number two' and extended by left downwind appropriately. The red and white aircraft that nearly intercepted us reported that he would be 'number three; both inbound aircraft in sight.' after landing; we taxied to the FBO. The third aircraft taxied the length of the runway before returning to 31 to depart. To answer the question as to what I might have done differently; I would have reported my position at five miles; rather than three to four miles. With two clear position reports and a geographic reference; I do not believe that other pilots familiar with S27 would have strayed toward the most common inbound arrival pattern.

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Original NASA ASRS Text

Title: A near miss was reported near S27 in spite of three involved aircraft making proper CTAF reports.

Narrative: This morning I departed S27 flew over the nearby mountains and returned across 'lower valley' toward S27; slowing descending to pattern altitude of 3;800 MSL. Approximately four to five miles southeast of S27; I heard an aircraft calling Kalispell City; 'five to the west;' altitude unknown. I then reported my position; 'three to four to the southeast; over the river; inbound for landing; will be entering a left downwind for Runway 13.' At this time a third aircraft reported 'inbound for landing; will keep an eye out for you once I find him.' My course was a forty five degree intercept to left downwind; as reported; and offered a geographic reference as well; 'over the river.' I then reported to both aircraft that I was entering a left downwind for 13; and was nearly to the radio towers southeast of the field. Suddenly my passenger and I noted a red and white aircraft climbing; banking toward us; and taking evasive maneuvers with a turn to the pilot's right. I immediately banked right as well; passing perhaps within 300 FT horizontally of this third aircraft. Based on my position reports; it remains unclear to me why he was in this area; seemingly flying the pattern backward and/or on an intercept to inbound standard left pattern traffic. Now established on the left downwind for 13; I noted the sock was slightly favoring 31. I reported this; and indicated I would be crossing midfield to enter a left downwind for 31. The initial pilot was in sight; and he was in a more favorable position to land first. As such; we both communicated; and I indicated I would land 'number two' and extended by left downwind appropriately. The red and white aircraft that nearly intercepted us reported that he would be 'number three; both inbound aircraft in sight.' After landing; we taxied to the FBO. The third aircraft taxied the length of the runway before returning to 31 to depart. To answer the question as to what I might have done differently; I would have reported my position at five miles; rather than three to four miles. With two clear position reports and a geographic reference; I do not believe that other pilots familiar with S27 would have strayed toward the most common inbound arrival pattern.

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.