ZJX Controller described a loss of separation event involving opposite direction traffic; claiming the use of the dwell lock procedures led to confusion as to what aircraft were in a conflicting status.
Synopsis
ZJX Controller described a loss of separation event involving opposite direction traffic; claiming the use of the dwell lock procedures led to confusion as to what aircraft were in a conflicting status.
Narrative
A MD88 was on the route flying southbound at FL310. There were two aircraft climbing to FL300 going northbound; one of them being an A320. Both northbound aircraft were issued a traffic alert and to expect higher passing the MD88 flight. The MD88 was also issued the traffic climbing to FL300 and was switched over to Mayo Sectors frequency. Some time had passed and I heard the A320 being issued a climb to FL330 while I was updating my URET screen. Knowing that traffic had been called and a higher altitude was to be issued upon passing this clearance did not raise a red flag in my mind. I completed my update of the URET screen and went to resume my focus on the RADAR scope where the conflict alert had started flashing the MD88 and the A320. The A320 indicated an altitude of FL304 thus losing separation. The R-Side Developmental; seeing the CA (Conflict Alert) going off; immediately issued the A320 a turn of 20 degree to the right for traffic. The pilot of the A320 read back the clearance and said that he had the traffic in sight off of his left side; roughly 4 miles west of their position. The only factor that I can deduce from the loss of separation would be the use of the 'highlight' method as a means of which aircraft are on frequency. The R-Side Developmental highlights which aircraft have checked on and takes off the highlight when they have been issued a frequency change. The MD88 was not highlighted at the time; and as a result; I believe they were overlooked in the traffic scan thus causing the R-Side Developmental to climb the A320. The R-Side Developmental was obviously aware of the traffic present at one time due to the traffic called to both aircraft; but once taking the dwell lock off of the MD88; it put them into a sense that traffic was no longer a factor. To avoid this event; either myself or the R-Side trainer should have been looking at the Data Block of the A320 when the clearance was issued and to take evasive action. I; however; was looking the my URET screen; at the R-Side; and the trainer must of been focused elsewhere on the sector thinking that his trainee was simply climbing the A320 after they had passed the MD88. I recommend not using the dwell lock feature for establishing which aircraft are currently on frequency.
Second reporter narrative
I was training a Developmental. The Developmental called traffic to an A320. The traffic was an MD88 opposite direction at flight level 310. The A320 was climbing to FL300. The Developmental also called traffic to another aircraft climbing to FL300. The Developmental climbed an aircraft not involved in incident; then climbed the A320 before separation was achieved and conflict alert went off. Traffic was light following a rather busy session for the Developmental's level of training. Other than training we were using a highlight method of knowing aircraft was on frequency suggested by Management. The traffic was un-highlighted because he had been shipped; maybe leaving him highlighted would have helped the Developmental remember the traffic; or using some other method or no method would have been more beneficial. If the computer were able to highlight data blocks as red or yellow; instead of just on the D-Side; might be beneficial.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.