Narrative:

I was on a daytime VFR flight to lewiston via rengo and V187. I was 10 mi out and just reaching for the ptt switch to contact the tower when another aircraft (identing self as 'aircraft Y') called in from 15 mi out and a lower altitude announcing intention to land. I then announced myself and exchanged altitude and location information with the tower who then contacted the aircraft Y with this information. This conversation resulted in a statement by the tower of 'traffic no factor.' I was cleared to land and told to announce myself on a right base for runway 11. While on right base; off the end of runway 8 and announcing my position the tower warned of traffic in an urgent tone. I don't recall exactly what the tower said but it was a traffic warning and something like 'half mi' and an altitude. I responded 'negative contact' and very shortly afterward observed a twin engine regional carrier type aircraft passing directly beneath me. I do not know the vertical separation was between us. It seemed on the order of 300-400-500 ft but I am not an experienced judge of distance and as a student pilot flying into an unfamiliar controled field perched on the edge of a cliff I was focused on making the approach and landing; not to mention still feeling the adrenaline from the tower's traffic warning call. I do not know whether the other aircraft had me in sight. I did not hear any indication that the other aircraft had seen me. My mistake was in ceasing to be concerned about the other aircraft when I heard the tower proclaim; 'traffic not a factor.' I was 5 mi closer than the other aircraft and traveling at approximately 135 mph and I assumed the other aircraft must be very much faster than I and would get to the airport well ahead of me. Stupid assumption of course. The right base I was cleared for put me smack in the path of the aircraft Y landing straight-in on the other runway. I should have taken a detour or not started my descent until I knew for myself that the other aircraft was not a factor. Probably should have also planned my right base to stay clear of the approach on the intersecting runway. I am older and wiser now.

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Original NASA ASRS Text

Title: C175 PILOT REPORTS CONFLICT WITH LIGHT TWIN DURING VISUAL APPROACH TO LWS; AFTER BEING TOLD TRAFFIC NO FACTOR.

Narrative: I WAS ON A DAYTIME VFR FLT TO LEWISTON VIA RENGO AND V187. I WAS 10 MI OUT AND JUST REACHING FOR THE PTT SWITCH TO CONTACT THE TWR WHEN ANOTHER ACFT (IDENTING SELF AS 'ACFT Y') CALLED IN FROM 15 MI OUT AND A LOWER ALT ANNOUNCING INTENTION TO LAND. I THEN ANNOUNCED MYSELF AND EXCHANGED ALT AND LOCATION INFO WITH THE TWR WHO THEN CONTACTED THE ACFT Y WITH THIS INFO. THIS CONVERSATION RESULTED IN A STATEMENT BY THE TWR OF 'TFC NO FACTOR.' I WAS CLRED TO LAND AND TOLD TO ANNOUNCE MYSELF ON A R BASE FOR RWY 11. WHILE ON R BASE; OFF THE END OF RWY 8 AND ANNOUNCING MY POS THE TWR WARNED OF TFC IN AN URGENT TONE. I DON'T RECALL EXACTLY WHAT THE TWR SAID BUT IT WAS A TFC WARNING AND SOMETHING LIKE 'HALF MI' AND AN ALT. I RESPONDED 'NEGATIVE CONTACT' AND VERY SHORTLY AFTERWARD OBSERVED A TWIN ENG REGIONAL CARRIER TYPE ACFT PASSING DIRECTLY BENEATH ME. I DO NOT KNOW THE VERT SEPARATION WAS BTWN US. IT SEEMED ON THE ORDER OF 300-400-500 FT BUT I AM NOT AN EXPERIENCED JUDGE OF DISTANCE AND AS A STUDENT PLT FLYING INTO AN UNFAMILIAR CTLED FIELD PERCHED ON THE EDGE OF A CLIFF I WAS FOCUSED ON MAKING THE APCH AND LNDG; NOT TO MENTION STILL FEELING THE ADRENALINE FROM THE TWR'S TFC WARNING CALL. I DO NOT KNOW WHETHER THE OTHER ACFT HAD ME IN SIGHT. I DID NOT HEAR ANY INDICATION THAT THE OTHER ACFT HAD SEEN ME. MY MISTAKE WAS IN CEASING TO BE CONCERNED ABOUT THE OTHER ACFT WHEN I HEARD THE TWR PROCLAIM; 'TFC NOT A FACTOR.' I WAS 5 MI CLOSER THAN THE OTHER ACFT AND TRAVELING AT APPROX 135 MPH AND I ASSUMED THE OTHER ACFT MUST BE VERY MUCH FASTER THAN I AND WOULD GET TO THE ARPT WELL AHEAD OF ME. STUPID ASSUMPTION OF COURSE. THE R BASE I WAS CLRED FOR PUT ME SMACK IN THE PATH OF THE ACFT Y LNDG STRAIGHT-IN ON THE OTHER RWY. I SHOULD HAVE TAKEN A DETOUR OR NOT STARTED MY DSCNT UNTIL I KNEW FOR MYSELF THAT THE OTHER ACFT WAS NOT A FACTOR. PROBABLY SHOULD HAVE ALSO PLANNED MY R BASE TO STAY CLEAR OF THE APCH ON THE INTERSECTING RWY. I AM OLDER AND WISER NOW.

Data retrieved from NASA's ASRS site as of May 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.