Narrative:

We wish to report a near mid air collision (near midair collision) that occurred in the traffic pattern of puw (pullman-moscow regional airport; pullman; washington). The following info contain the 'items to be reported' as recommended by section 7-6-3 (near midair collision reporting) in chapter 7 of the airman's information manual. Following these items will be our detailed description of the events that transpired. On a 5 mile left base for runway 23 at puw; 4;500 ft MSL. The other aircraft was suspected to be a piper cherokee; destination unknown at this time. We had cancelled an IFR flightplan approximately 5 minutes prior to incident for a VFR landing at an uncontrolled field. Prior to cancellation; ATC (seattle center) issued an alert for numerous VFR targets in the vicinity of the landing airport. We cancelled the flight plan early so that communications could be established and prioritized with the other traffic. It is unknown what type of flightplan the other aircraft was operating under; but it is assumed that no flightplan was filed. The local altimeter was 29.92 and was retrieved from the puw AWOS approximately 10 minutes prior to the incident. Detailed weather conditions at altitude or flight level: the entire area was experiencing VMC conditions with light westerly winds. The most recent AWOS report 'wind 280 at 8; visibility 10; sky condition clear; temperature 20; dewpoint 9; altimeter setting 29.92. Approximate courses of both aircraft (climb or descent): our aircraft was on an approximate heading of 015 magnetic levels at 4;500 ft MSL. The other aircraft was on an approximate heading of 100 magnetic; also level at 4;500 ft MSL. At first sighting; the other aircraft was approximately 100 ft away; directly off the left wing. Passengers estimate that it passed behind and below us with soft separation. The aircraft was in sight for not more than 1 second. We made a hard right bank; and the conflicting aircraft likewise made a hard right bank and disappeared behind and under our aircraft. A passenger reported seeing the aircraft at an almost 90 degree bank angle. This picture could have been distorted because of our own bank angle at the time. No injuries. As is typical on a VFR summer day; there were a few small general aviation aircraft in the vicinity of puw. Coe and a few other nearby airports also operate on 122.8 and the pilot not flying was receiving numerous reports from these fields as well handed control of radio 1 (123.95) to the pilot flying so that he could communicate with local traffic on CTAF 122.8 on radio 2. The initial call out was made: 'pullman area traffic; large aircraft; is 25 miles south over the river; descending out of one two thousand feet; inbound for left hand traffic; runway 23; estimating arrival time in 5 minutes;-any other traffic in the area please advise; pullman.' there were other aircraft that followed with reports. One was a cessna 172 that was approximately 5 miles north of pullman at 4;500 ft MSL. His intent was to cross midfield and join left hand traffic for runway 23. Another (type unknown) was crossing the field at 6;500 ft MSL; southwest bound for walla walla (alw). At 15 NM from destination and with the airport environment in sight; the pilot flying elected to cancel the IFR flightplan with seattle center. The pilot not flying complied with this request and was advised by ATC about numerous VFR targets in the puw area and to 'have a nice day.' another call out to pullman traffic was made at 15 NM (descending through approximately 8;000 ft). Following this call out; the pilot not flying asked the cessna 172 traffic; who was inbound for runway 23; what his intentions were. He replied that rather than crossing mid-field; he would 'keep it to the east' for us. At this point the pilot flying and pilot not flying agreed that the best course of action was to 'keep it to the west' and head straight for a left base rather than getting congested in the downwind. This would widen our separationmargin with the other aircraft and speed things along for him to get in behind us. Once the decision was made; this intention was broadcast clearly to the other aircraft. Shortly after this announcement; a transmission was heard from an aircraft departing runway 23 at puw. The transmission read '... Departing west bound for moscow'. The pilot flying said 'huh?' because moscow is east of the airport; not west. A few seconds later; the transmission came back 'correction; east bound for moscow.' at 10 miles; we were descending through 6;000 ft at approximately 200 KTS TAS and another position report was made: 'pullman area traffic; large aircraft; 10 miles south of the field; descending out of 6;000 ft; to join an extended left base for runway 23; full stop at pullman; estimating arrival in 2 minutes; other landing traffic; what is your position?' the other aircraft responded that they were just east of the field over the city of pullman and would follow us in. Our aircraft is TCAS I equipped; and was displaying 2 targets in the puw area. One aircraft was indicating 6;500 ft MSL and another was indicating 4;500 ft MSL. These were the same altitudes being reported by the aircraft en route to alw and the aircraft landing runway 23 behind us; and the positions seemed to match up. The pilot flying thinks he remembers seeing another target disappear from the display; while the pilot not flying didn't notice this. The traffic was a concern for the crew so the pilot flying made the decision to turn off the autopilot and enter the pattern slightly higher than normal (4;500 ft as opposed to 4;000 ft). An aural 'traffic' alert was emitted from the TCAS; but the display only depicted the 2 aircraft. The one at our altitude was behind us and the one at 6;500 ft was very close to us; but 2;000 ft above. As we entered a 5 NM left base; the pilot not flying put his finger on the push-to-talk with the intent of another position report when the pilot flying looked out his left side window and noticed an aircraft (low wing single engine piper; possibly a cherokee) heading straight for us at our altitude (4;500 ft). He estimated at initial glance that the aircraft appeared to be 100 ft away. He said something (neither can remember exactly what) and initiated a hard 40 degree right hand bank. Just prior to the bank; as the remark was said; the pilot not flying leaned forward to look out the same window and saw the aircraft at what he estimated as approximately 50 ft away. Neither of the crew saw the aircraft again; but passengers who witnessed the event agree that the aircraft was within 100 ft. They state that it too made a hard right hand evasive maneuver (up to 90 degrees) before disappearing behind and underneath our tail. The pilot not flying immediately broadcast over 122.8 'aircraft over the kibbie dome at 4;500 ft are you on the radio???' the pilot acknowledged that he was. The pilot not flying stated 'we made several calls about entering a left base;' to which he replied 'I thought you said you were entering downwind?' lastly the pilot not flying asked; 'do you have an operating transponder on board? If so; please turn it on. We have all of the other aircraft on TCAS; but never saw you coming.' he responded 'it is on and we will have it looked at.' the crew and passengers were shaken and startled by the events; but initiated a routine and uneventful landing on runway 23 at puw. Upon deplaning; the eight of us shared our descriptions and accounts of the event to get the clearest picture possible of what just transpired. The following list is a collection of these factors: like many CTAF frequencies; 122.8 is used widely in the area and the crew received traffic reports from numerous airports. Not only was puw busy this day; but so was coe; colfax municipal; and cottonwood; identification. The radio was very cluttered; and it's possible that either our transmissions; or the transmissions from the other aircraft were blocked. The aircraft targets depicted on the TCAS display provided a distraction that kept eyes inside the cockpit. Particularly when an aural warning is issued; the crew looks to the display to see where the traffic is located. In this instance; it was only displaying traffic above and behind which added confusion to the situation because you shouldn't get aural warnings for those situations. The two aircraft that we were aware of exercised good two-way radio communications with us and others in the vicinity. We all spoke to each other and included each other's positions in our situational awareness. The departing aircraft with whom we had the conflict made one call upon taking off; but didn't speak again even though multiple aircraft were in the pattern. Neither a radio nor transponders are required equipment at puw; but their proper use would dramatically reduce the risk of incidents such as this. We can't speak for the operational integrity of the other transponder. But there was no TCAS target forward of our position as depicted on our display. We did receive an aural warning; and the pilot flying remembers seeing a target disappear earlier on the arrival; which could indicate an intermittent transponder signal. A sunny VFR summer day can often pose greater threat at an uncontrolled field than an 'at-minimums' day where only IFR traffic is operating. Summer traffic at puw is often heavy with private pilots and ag pilots who don't always practice proper traffic pattern techniques or radio communications. We hope you find this detailed account of a near mid air collision to be useful.

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Original NASA ASRS Text

Title: A corporate jet Captain descending for landing at CTAF PUW reported a near miss with an aircraft departing.

Narrative: We wish to report a near mid air collision (NMAC) that occurred in the traffic pattern of PUW (Pullman-Moscow Regional Airport; Pullman; Washington). The following info contain the 'items to be reported' as recommended by section 7-6-3 (Near Midair Collision Reporting) in Chapter 7 of the Airman's Information Manual. Following these items will be our detailed description of the events that transpired. On a 5 mile left base for Runway 23 at PUW; 4;500 FT MSL. The other aircraft was suspected to be a Piper Cherokee; destination unknown at this time. We had cancelled an IFR flightplan approximately 5 minutes prior to incident for a VFR landing at an uncontrolled field. Prior to cancellation; ATC (Seattle Center) issued an alert for numerous VFR targets in the vicinity of the landing airport. We cancelled the flight plan early so that communications could be established and prioritized with the other traffic. It is unknown what type of flightplan the other aircraft was operating under; but it is assumed that no flightplan was filed. The local altimeter was 29.92 and was retrieved from the PUW AWOS approximately 10 minutes prior to the incident. Detailed weather conditions at altitude or flight level: The entire area was experiencing VMC conditions with light westerly winds. The most recent AWOS report 'wind 280 at 8; visibility 10; sky condition clear; temperature 20; dewpoint 9; altimeter setting 29.92. Approximate courses of both aircraft (climb or descent): our aircraft was on an approximate heading of 015 magnetic levels at 4;500 FT MSL. The other aircraft was on an approximate heading of 100 magnetic; also level at 4;500 FT MSL. At first sighting; the other aircraft was approximately 100 FT away; directly off the left wing. Passengers estimate that it passed behind and below us with soft separation. The aircraft was in sight for not more than 1 second. We made a hard right bank; and the conflicting aircraft likewise made a hard right bank and disappeared behind and under our aircraft. A passenger reported seeing the aircraft at an almost 90 degree bank angle. This picture could have been distorted because of our own bank angle at the time. No injuries. As is typical on a VFR summer day; there were a few small general aviation aircraft in the vicinity of PUW. COE and a few other nearby airports also operate on 122.8 and the pilot not flying was receiving numerous reports from these fields as well handed control of Radio 1 (123.95) to the pilot flying so that he could communicate with local traffic on CTAF 122.8 on Radio 2. The initial call out was made: 'Pullman area traffic; large aircraft; is 25 miles south over the river; descending out of one two thousand feet; inbound for left hand traffic; Runway 23; estimating arrival time in 5 minutes;-any other traffic in the area please advise; Pullman.' There were other aircraft that followed with reports. One was a Cessna 172 that was approximately 5 miles north of Pullman at 4;500 FT MSL. His intent was to cross midfield and join left hand traffic for Runway 23. Another (type unknown) was crossing the field at 6;500 FT MSL; southwest bound for Walla Walla (ALW). At 15 NM from destination and with the airport environment in sight; the pilot flying elected to cancel the IFR flightplan with Seattle Center. The pilot not flying complied with this request and was advised by ATC about numerous VFR targets in the PUW area and to 'have a nice day.' Another call out to Pullman traffic was made at 15 NM (descending through approximately 8;000 FT). Following this call out; the pilot not flying asked the Cessna 172 traffic; who was inbound for Runway 23; what his intentions were. He replied that rather than crossing mid-field; he would 'keep it to the east' for us. At this point the pilot flying and pilot not flying agreed that the best course of action was to 'keep it to the west' and head straight for a left base rather than getting congested in the downwind. This would widen our separationmargin with the other aircraft and speed things along for him to get in behind us. Once the decision was made; this intention was broadcast clearly to the other aircraft. Shortly after this announcement; a transmission was heard from an aircraft departing Runway 23 at PUW. The transmission read '... departing west bound for Moscow'. The pilot flying said 'huh?' because Moscow is east of the airport; not west. A few seconds later; the transmission came back 'correction; east bound for Moscow.' At 10 miles; we were descending through 6;000 FT at approximately 200 KTS TAS and another position report was made: 'Pullman area traffic; large aircraft; 10 miles south of the field; descending out of 6;000 FT; to join an extended left base for Runway 23; full stop at Pullman; estimating arrival in 2 minutes; other landing traffic; what is your position?' The other aircraft responded that they were just east of the field over the city of Pullman and would follow us in. Our aircraft is TCAS I equipped; and was displaying 2 targets in the PUW area. One aircraft was indicating 6;500 FT MSL and another was indicating 4;500 FT MSL. These were the same altitudes being reported by the aircraft en route to ALW and the aircraft landing Runway 23 behind us; and the positions seemed to match up. The pilot flying thinks he remembers seeing another target disappear from the display; while the pilot not flying didn't notice this. The traffic was a concern for the crew so the pilot flying made the decision to turn off the autopilot and enter the pattern slightly higher than normal (4;500 FT as opposed to 4;000 FT). An aural 'TRAFFIC' alert was emitted from the TCAS; but the display only depicted the 2 aircraft. The one at our altitude was behind us and the one at 6;500 FT was very close to us; but 2;000 FT above. As we entered a 5 NM left base; the pilot not flying put his finger on the push-to-talk with the intent of another position report when the pilot flying looked out his left side window and noticed an aircraft (low wing single engine Piper; possibly a Cherokee) heading straight for us at our altitude (4;500 FT). He estimated at initial glance that the aircraft appeared to be 100 FT away. He said something (neither can remember exactly what) and initiated a hard 40 degree right hand bank. Just prior to the bank; as the remark was said; the pilot not flying leaned forward to look out the same window and saw the aircraft at what he estimated as approximately 50 FT away. Neither of the crew saw the aircraft again; but passengers who witnessed the event agree that the aircraft was within 100 FT. They state that it too made a hard right hand evasive maneuver (up to 90 degrees) before disappearing behind and underneath our tail. The pilot not flying immediately broadcast over 122.8 'aircraft over the Kibbie Dome at 4;500 FT are you on the radio???' The pilot acknowledged that he was. The pilot not flying stated 'we made several calls about entering a left base;' to which he replied 'I thought you said you were entering downwind?' Lastly the pilot not flying asked; 'Do you have an operating transponder on board? If so; please turn it on. We have all of the other aircraft on TCAS; but never saw you coming.' He responded 'it is on and we will have it looked at.' The crew and passengers were shaken and startled by the events; but initiated a routine and uneventful landing on Runway 23 at PUW. Upon deplaning; the eight of us shared our descriptions and accounts of the event to get the clearest picture possible of what just transpired. The following list is a collection of these factors: Like many CTAF frequencies; 122.8 is used widely in the area and the crew received traffic reports from numerous airports. Not only was PUW busy this day; but so was COE; Colfax Municipal; and Cottonwood; ID. The radio was very cluttered; and it's possible that either our transmissions; or the transmissions from the other aircraft were blocked. The aircraft targets depicted on the TCAS display provided a distraction that kept eyes inside the cockpit. Particularly when an aural warning is issued; the crew looks to the display to see where the traffic is located. In this instance; it was only displaying traffic above and behind which added confusion to the situation because you shouldn't get aural warnings for those situations. The two aircraft that we were aware of exercised good two-way radio communications with us and others in the vicinity. We all spoke to each other and included each other's positions in our situational awareness. The departing aircraft with whom we had the conflict made one call upon taking off; but didn't speak again even though multiple aircraft were in the pattern. Neither a radio nor transponders are required equipment at PUW; but their proper use would dramatically reduce the risk of incidents such as this. We can't speak for the operational integrity of the other transponder. But there was no TCAS target forward of our position as depicted on our display. We did receive an aural warning; and the pilot flying remembers seeing a target disappear earlier on the arrival; which could indicate an intermittent transponder signal. A sunny VFR summer day can often pose greater threat at an uncontrolled field than an 'at-minimums' day where only IFR traffic is operating. Summer traffic at PUW is often heavy with private pilots and AG pilots who don't always practice proper traffic pattern techniques or radio communications. We hope you find this detailed account of a near mid air collision to be useful.

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.