Narrative:

I was piloting aircraft X northwest bound at 8;500 ft in daytime visual meteorological conditions approximately 15 miles northeast of the montrose regional airport; montrose; colorado (mtj). There were clouds and rain showers in the vicinity. I was located at least 0.5 to 1 mile horizontal; 1;000 ft above; and 2;000 ft below the nearest clouds. The pcas (portable collision avoidance system) in my aircraft began to display air carrier Y; a regional jet; at 3-4 miles and approximately 800 ft above aircraft X. I increased my visual scan outside the aircraft and in under a minute made visual contact with the regional jet at about my 3-4 o'clock position. The regional jet appeared to be at a distance of 3 to 2 miles and 500-700 ft above my aircraft. Its course was west to northwest roughly parallel to mine. I was able to visually confirm that the regional jet was passing by above and well to my right; and did not represent a collision hazard. I tuned my aircraft radio to the montrose airport unicom and heard the pilot of the regional jet exclaim on the frequency that he had just gotten a RA (resolution advisory) from the TCAS aboard his aircraft. The regional jet pilot displayed anger in his transmissions about the presence of my aircraft. The regional jet proceeded to complete its approach and make an uneventful landing at mtj; and I proceed also uneventfully on course to my destination. Mtj is an uncontrolled airfield which is surrounded by class east airspace. The surrounding mountains likely prevent center/approach control from providing radar service down to the airport surface. The pilot of the regional jet commented that he did not receive any radar advisories from ATC as to my presence. Since the TCAS on the regional jet received my transponder replies in order to issue the RA; it is likely that I was below ATC radar coverage at the time of the event. It is likely that the regional jet was in and out of IMC during its approach to mtj. There was an area of clouds; which was IMC east of my position and the regional jet may have passed through and exited this prior to my making visual contact. The regional jet may have had concerns about encountering additional IMC prior to landing at mtj. Given the lack of radar advisories from ATC; I can understand the concern of the regional jet pilot upon receiving an unexpected RA while he was either still in IMC or just emerged into VMC (and perhaps soon to go back into IMC). I expect that it could be disorienting and distracting given the other tasks underway as a part of approach and landing. This event provides a good example of the hazards which exist around mountain airports which don't have ATC radar provided to the surface and are served by high speed jet traffic. Despite the fact that the systems in place for assuring avoidance of conflict between aircraft worked in this case; i.e. Both the regional jet's RA and my positive visual contact with the regional jet were successful in resolving the event; the increasing amount of jet traffic in this environment means that recognition and resolution of traffic conflicts has to take place in ever shorter time frames. I believe it would have reduced stress on the regional jet pilot; and it would have increased safety if I had been flying my aircraft at a greater distance from clouds when the regional jet pilot received the RA and if I had been listening and communicating on the unicom frequency prior to the alert on my pcas.

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Original NASA ASRS Text

Title: A small aircraft pilot in VMC conditions detected an RJ on his Portable Collision Avoidance System as the other aircraft approached the mountainous airport MTJ. No maneuvering was required for avoidance but the RJ pilot complained about an RA.

Narrative: I was piloting Aircraft X northwest bound at 8;500 FT in daytime visual meteorological conditions approximately 15 miles northeast of the Montrose Regional Airport; Montrose; Colorado (MTJ). There were clouds and rain showers in the vicinity. I was located at least 0.5 to 1 mile horizontal; 1;000 FT above; and 2;000 FT below the nearest clouds. The PCAS (Portable Collision Avoidance System) in my aircraft began to display Air Carrier Y; a regional jet; at 3-4 miles and approximately 800 FT above Aircraft X. I increased my visual scan outside the aircraft and in under a minute made visual contact with the regional jet at about my 3-4 o'clock position. The regional jet appeared to be at a distance of 3 to 2 miles and 500-700 FT above my aircraft. Its course was west to northwest roughly parallel to mine. I was able to visually confirm that the regional jet was passing by above and well to my right; and did not represent a collision hazard. I tuned my aircraft radio to the Montrose Airport Unicom and heard the pilot of the regional jet exclaim on the frequency that he had just gotten a RA (resolution advisory) from the TCAS aboard his aircraft. The regional jet pilot displayed anger in his transmissions about the presence of my aircraft. The regional jet proceeded to complete its approach and make an uneventful landing at MTJ; and I proceed also uneventfully on course to my destination. MTJ is an uncontrolled airfield which is surrounded by Class E Airspace. The surrounding mountains likely prevent Center/Approach Control from providing radar service down to the airport surface. The pilot of the regional jet commented that he did not receive any radar advisories from ATC as to my presence. Since the TCAS on the regional jet received my transponder replies in order to issue the RA; it is likely that I was below ATC radar coverage at the time of the event. It is likely that the regional jet was in and out of IMC during its approach to MTJ. There was an area of clouds; which was IMC east of my position and the regional jet may have passed through and exited this prior to my making visual contact. The regional jet may have had concerns about encountering additional IMC prior to landing at MTJ. Given the lack of radar advisories from ATC; I can understand the concern of the regional jet pilot upon receiving an unexpected RA while he was either still in IMC or just emerged into VMC (and perhaps soon to go back into IMC). I expect that it could be disorienting and distracting given the other tasks underway as a part of approach and landing. This event provides a good example of the hazards which exist around mountain airports which don't have ATC radar provided to the surface and are served by high speed jet traffic. Despite the fact that the systems in place for assuring avoidance of conflict between aircraft worked in this case; i.e. both the regional jet's RA and my positive visual contact with the regional jet were successful in resolving the event; the increasing amount of jet traffic in this environment means that recognition and resolution of traffic conflicts has to take place in ever shorter time frames. I believe it would have reduced stress on the regional jet pilot; and it would have increased safety if I had been flying my aircraft at a greater distance from clouds when the regional jet pilot received the RA and if I had been listening and communicating on the Unicom frequency prior to the alert on my PCAS.

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.