Approach Controller providing OJT and the pilot involved described a conflict event during a position relief period. The reporter noted the limited communications jacks available when training is being conducted.
Synopsis
Approach Controller providing OJT and the pilot involved described a conflict event during a position relief period. The reporter noted the limited communications jacks available when training is being conducted.
Narrative
With training in progress; a PA46T was issued a descent to 3;000 FT. The trainee quickly amended the altitude to 10;000 FT and said; 'Leaving 10;000 FT; turn right heading 360 vector for descent.' The pilot read back; 'Descend to 10;000 FT; then turn right heading 360; and descend and maintain 3;000 FT. The read back of 'descend and maintain 3;000 FT' was not caught by the trainee or the trainer. A relieving Controller unplugged me and I noticed the PA46T descending through 10;000 FT and notified both the trainee and the relieving Controller. The trainee hesitated a bit; then told the PA46T to maintain 10;000 FT; and issued traffic. The relieving Controller didn't say anything to the pilot and just told the trainee to issue a heading. The trainee issued a 020 heading to the PA46. Then the relieving Controller told an Excel to turn right heading 360. The Excel pilot replied that they were responding to a TCAS/RA and had the other aircraft in sight. When a Controller is relieving a training session they should plug into another headset jack and monitor the frequencies while getting the briefing instead of unplugging the trainer.
Second reporter narrative
I was training on Arrival/Departure RADAR with an OJTI. An Excel had departed and was eastbound; level at 9;000 FT. A P46T arriving; was heading northwest bound; direct to the airport; level at 11;000 FT. I had a few other aircraft I was working in the airspace; requiring some coordination with other facilities and a VFR call-up happening around the same time. After some coordination with neighboring Tower and taking control of another VFR [aircraft]; my scan brought me back to the PA46T and I realized I had waited longer than I intended to descend him; he was getting close to his destination and was still at 11;000 FT. In my haste; I issued the PA46T a descent to 3;000 FT. Immediately recognizing my mistake; I realized I would have to issue descent to 10;000 FT because of the Excel traffic northwest of the PA46T's position. I went right back to the PA46T to correct his altitude. I also knew I would have to give him vectors for descent in order to clear him for the approach at an acceptable location. In my frustration due to getting behind I accidentally said; 'Descend and maintain 1;000 FT;' then corrected myself to say; 'Descend and maintain 10;000 FT (one zero thousand); leaving 10;000 FT (one zero thousand) turn right heading 360 vector for descent.' Also at this time; the relieving Controller was behind me telling me he was ready to receive the relief briefing. It was at this time I missed the read back from the PA46T; where he stated he was descending to 3;000 FT.I'm not certain at what point the relieving Controller unplugged the OJTI to monitor the briefing; but due to this the OJTI also missed the read back. Shortly into the briefing; my OJTI exclaimed that the PA46T was descending out of 10;000 FT and converging with the Excel. I immediately told the PA46T to maintain 10;000 FT and issued the traffic 5 miles northwest of his position; [which was] eastbound at 9;000 FT. The PA46T was at approximately 9;500 FT when I turned him to the 020 heading. The relieving Controller; who was now plugged in; jumped in and transmitted for the Excel to turn left heading 360. At this time; the Excel said he showed the traffic on TCAS; was responding to the resolution advisory; and that he had the PA46T in sight. The relieving Controller told the Excel to maintain visual separation with the PA46T and maneuver as necessary. In my hurried state; my phraseology was poor and confusing to the pilot. I should have said; 'REACHING (not leaving) 10;000 FT turn right heading 360 vector for VISUAL APPROACH (not for descent).' I was also distracted by starting the relief briefing. [It] caused me to miss the read back where the PA46T thought he was still cleared to descend to 3;000 FT; most likely [due to] my phraseology. I believe my OJTI would have been able to override quicker if there was an additional jack; allowing him/her to remain plugged in at the same time the relieving Controller was plugged in trying to receive the relief briefing. Alternatively; the relieving Controller could plug into another position to monitor during the briefing so the trainer and trainee are still both plugged in.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.