Narrative:

I was working pearson advisory. Aircraft X called inbound somewhere from the north. He said he wanted a touch and go at pearson (vuo); then to go to hillsboro (hio). Aircraft X had a poor radio and thick accent. I had to make a couple transmissions to make sure he had the pearson one minute weather due to my difficulty understanding him. After I obtained the necessary information; I told him to fly direct hillsboro after completion of his touch and go; as there were no aircraft on the scope at the time. Aircraft X advised that he was full stop and taxiing back on the runway. Realizing I had created a potentially unsafe situation should traffic appear; I told aircraft X to depart over the north bank eastbound and expect to cross over the tower to get to hio. When aircraft X called ready to depart; I instructed him to the same due to aircraft Y and aircraft Z inbound to 10R. Aircraft X readback that he would head eastbound. When aircraft X was airborne I called traffic on aircraft Y who was about six or seven mile final. Aircraft X called aircraft Y in sight. I told him; 'turning eastbound; contact tower 118.7.' aircraft X never turned eastbound. He tracked about a half mile north of the 10L final westbound. Aircraft Z was on base about six mile final. To create space between him and aircraft Y; final took aircraft Z through final. Aircraft Z was descending to 025 while aircraft X was climbing through 020. Aircraft Z flew over aircraft X with about 004 verticle separation when he responded to a TCAS RA.first and foremost; I should never have given aircraft X direct hio after his touch and go. At vuo; I have no control of how long he will take on the runway; and won't have eyes on him to know immediately when he does something other than what he said; what I told him; or the myriad of other things that could go wrong and result in a loss of separation with traffic on final. Secondly; I should have told him; directly and bluntly; to turn to the east (either: 'turn eastbound now... [Readback]... Contact tower' or 'start your right turn to the east now') prior to switching him to tower. Barring the first two things; I could have also told him to depart over the north bank *westbound* and to maintain VFR at or below 015 and instructed him to contact final (after coordinating). The mvas to the west make this a safe instruction and letting him go westbound is more of what he is expecting since hio is southwest of both vuo and pdx. This will keep him below the traffic on final (040 is the recommended crossing altitude over the confluence for the columbia visual approach; while 020 is the crossing altitude at powlz for the ILS 10R and blazr for the ILS 10R) and allows final to tunnel him underneath the arriving traffic safely and easily. This was a perfect example of a problem finding its way through the block of swiss cheese. Final vectored aircraft Z too close for a visual than the weather allowed and; too close to aircraft Y; which required the s-turn through final. The tower controller had difficulty radar identifying aircraft X in order to issue a meaningful instruction to keep him away from final traffic. I am not exonerating myself from responsibility; I furthered the problem by not ensuring aircraft X turned east prior to frequency change; or allowed him to continue west with an altitude restriction and switched him to final.

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Original NASA ASRS Text

Title: PDX Controller reports of a NMAC due to an aircraft not doing what he requested the pilot to do. Aircraft departs an airport just NW of PDX and is enroute to an airport just on the east side of PDX. Aircraft gets close to traffic on final for PDX.

Narrative: I was working Pearson Advisory. Aircraft X called inbound somewhere from the north. He said he wanted a touch and go at Pearson (VUO); then to go to Hillsboro (HIO). Aircraft X had a poor radio and thick accent. I had to make a couple transmissions to make sure he had the Pearson one minute weather due to my difficulty understanding him. After I obtained the necessary information; I told him to fly direct Hillsboro after completion of his touch and go; as there were no aircraft on the scope at the time. Aircraft X advised that he was full stop and taxiing back on the runway. Realizing I had created a potentially unsafe situation should traffic appear; I told Aircraft X to depart over the north bank eastbound and expect to cross over the tower to get to HIO. When Aircraft X called ready to depart; I instructed him to the same due to Aircraft Y and Aircraft Z inbound to 10R. Aircraft X readback that he would head eastbound. When Aircraft X was airborne I called traffic on Aircraft Y who was about six or seven mile final. Aircraft X called Aircraft Y in sight. I told him; 'Turning eastbound; contact tower 118.7.' Aircraft X never turned eastbound. He tracked about a half mile north of the 10L final westbound. Aircraft Z was on base about six mile final. To create space between him and Aircraft Y; final took Aircraft Z through final. Aircraft Z was descending to 025 while Aircraft X was climbing through 020. Aircraft Z flew over Aircraft X with about 004 verticle separation when he responded to a TCAS RA.First and foremost; I should never have given Aircraft X direct HIO after his touch and go. At VUO; I have no control of how long he will take on the runway; and won't have eyes on him to know immediately when he does something other than what he said; what I told him; or the myriad of other things that could go wrong and result in a loss of separation with traffic on final. Secondly; I should have told him; directly and bluntly; to turn to the east (either: 'turn eastbound now... [readback]... contact tower' or 'start your right turn to the east now') prior to switching him to tower. Barring the first two things; I could have also told him to depart over the north bank *westbound* and to maintain VFR at or below 015 and instructed him to contact final (after coordinating). The MVAs to the west make this a safe instruction and letting him go westbound is more of what he is expecting since HIO is southwest of both VUO and PDX. This will keep him below the traffic on final (040 is the recommended crossing altitude over the Confluence for the Columbia Visual Approach; while 020 is the crossing altitude at POWLZ for the ILS 10R and BLAZR for the ILS 10R) and allows final to tunnel him underneath the arriving traffic safely and easily. This was a perfect example of a problem finding its way through the block of swiss cheese. Final vectored Aircraft Z too close for a visual than the weather allowed and; too close to Aircraft Y; which required the S-turn through final. The tower controller had difficulty RADAR identifying Aircraft X in order to issue a meaningful instruction to keep him away from final traffic. I am not exonerating myself from responsibility; I furthered the problem by not ensuring Aircraft X turned east prior to frequency change; or allowed him to continue west with an altitude restriction and switched him to final.

Data retrieved from NASA's ASRS site 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.