ZJX controller described a loss of separation event involving opposite direction traffic; claiming t...

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.

Original NASA ASRS Text

Title: 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.

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.

Attributes
ACN	921658
Time
Date	201012
Local Time Of Day	0001-0600
Place
Locale Reference	ZJX.ARTCC
State Reference	FL
Aircraft 1
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Aircraft 2
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Developmental
Person 2
Function	Instructor Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy

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.