Narrative:

I was training a developmental on radar east sector at aus TRACON. The developmental descended an MD80 to 3;000 ft about 10 miles northeast of aus on a heading of 180 degrees. A C414 departed aus heading 030 degrees climbing to 4;000 ft. The trainee told the C414 to climb and maintain 12;000 ft and turn right direct to hookk intersection (approximately a 060 degree heading). As I was telling the trainee that this was not going to work; the C414 asked for a verification of the assigned vector and altitude. Instead of hearing me; he/she heard the pilot and verified the climb and vector. Again I told the trainee that this was not going to work and to correct the situation. He/she called the C414 and told the pilot to fly heading 350 degrees and maintain 3;000 ft. The pilot did not respond. Again the trainee called the C414 with no immediate response. It turns out that the trainee had transposed the last 2 letters of the C414's call sign. I did not realize that he/she had made this mistake. The trainee advised the MD80 to maintain 4;000 ft and turn left; I do not recall what heading was assigned. The MD80 pilot acknowledged and complied. Either before or after the communication with the MD80; the C414 asked if the previous calls were for them because the last 2 letters were transposed. The trainee responded affirmative and told the C414 to fly heading 250 degrees maintain 3;000 ft; traffic stopped at 4;000 ft. The C414 pilot replied 'turn to 350 degrees; maintain 4;000 ft.' the trainee told the C414 to maintain 3;000 ft traffic alert. The C414 pilot replied 'maintain 3;000 ft traffic in sight.' at this point; separation had already been lost. The descent of the MD80 to 3;000 ft before clearing the departure corridor was not a wise decision by the trainee and I intended to cover this in our debrief. The error began when the trainee turned and climbed the C414 directly toward the MD80. In retrospect; I should have taken over at that point but I wanted the trainee to fix it. When the trainee twice used the transposed call sign; I did not catch the mistake and this is what I believe led to the loss of separation. At this point the C414 read back an incorrect altitude which more time was lost; leading to the aircraft getting even closer to each other.

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Original NASA ASRS Text

Title: AUS Controller providing OJT described operational error when failing to intercede and correct the developing loss of separation; listing Trainee transposing call sign/s and his/her failure to detect same as the primary causal factor.

Narrative: I was training a Developmental on Radar East sector at AUS TRACON. The Developmental descended an MD80 to 3;000 FT about 10 miles northeast of AUS on a heading of 180 degrees. A C414 departed AUS heading 030 degrees climbing to 4;000 FT. The Trainee told the C414 to climb and maintain 12;000 FT and turn right direct to HOOKK Intersection (approximately a 060 degree heading). As I was telling the Trainee that this was not going to work; the C414 asked for a verification of the assigned vector and altitude. Instead of hearing me; he/she heard the pilot and verified the climb and vector. Again I told the Trainee that this was not going to work and to correct the situation. He/she called the C414 and told the pilot to fly heading 350 degrees and maintain 3;000 FT. The pilot did not respond. Again the Trainee called the C414 with no immediate response. It turns out that the Trainee had transposed the last 2 letters of the C414's call sign. I did not realize that he/she had made this mistake. The Trainee advised the MD80 to maintain 4;000 FT and turn left; I do not recall what heading was assigned. The MD80 pilot acknowledged and complied. Either before or after the communication with the MD80; the C414 asked if the previous calls were for them because the last 2 letters were transposed. The Trainee responded affirmative and told the C414 to fly heading 250 degrees maintain 3;000 FT; traffic stopped at 4;000 FT. The C414 Pilot replied 'turn to 350 degrees; maintain 4;000 FT.' The Trainee told the C414 to maintain 3;000 FT traffic alert. The C414 pilot replied 'Maintain 3;000 FT traffic in sight.' At this point; separation had already been lost. The descent of the MD80 to 3;000 FT before clearing the departure corridor was not a wise decision by the Trainee and I intended to cover this in our debrief. The error began when the Trainee turned and climbed the C414 directly toward the MD80. In retrospect; I should have taken over at that point but I wanted the Trainee to fix it. When the Trainee twice used the transposed call sign; I did not catch the mistake and this is what I believe led to the loss of separation. At this point the C414 read back an incorrect altitude which more time was lost; leading to the aircraft getting even closer to each other.

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.