Several enroute controllers described a loss of separation event involving a dropped data block.

Attributes
ACN	987523
Time
Date	201201
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Aircraft 1
Make Model Name	Challenger 300
Operating Under FAR Part	Part 91
Flight Phase	Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	PA-46 Malibu/Malibu Mirage/Malibu Matrix
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Enroute
Qualification	Air Traffic Control Developmental
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

Narrative:

At the time of the event I was training; we were looking for a NORDO VFR aircraft; passing an inbound to their destinations tower; other d-side functions; and as a trainer; I was taking notes for us to discuss later. I had prompted the trainee to point a CL30 out to the neighboring center. After the point out was complete; the radar controller climbed the CL30 to FL230 and began a hand off to the high sector. The climb placed the CL30 in a possible conflict with a PA46 level at FL190 southbound. The neighboring center had the hand off on the PA46 and the data block was no longer displayed on our radar scope. My attention was consumed with training and looking for the NORDO VFR and I was unaware of the possible conflict. I noticed conflict alert activated and observed a possible conflict. I advised our supervisor of a possible loss of separation. Reflecting back; having the sectors split would have been helpful. The complexity increased since the 40 minutes pass from the start of our shift.

Original NASA ASRS Text

Title: Several Enroute controllers described a loss of separation event involving a dropped Data Block.

Narrative: At the time of the event I was training; we were looking for a NORDO VFR aircraft; passing an inbound to their destinations Tower; other D-Side functions; and as a trainer; I was taking notes for us to discuss later. I had prompted the trainee to point a CL30 out to the neighboring Center. After the point out was complete; the RADAR Controller climbed the CL30 to FL230 and began a hand off to the high sector. The climb placed the CL30 in a possible conflict with a PA46 level at FL190 southbound. The neighboring Center had the hand off on the PA46 and the Data Block was no longer displayed on our RADAR scope. My attention was consumed with training and looking for the NORDO VFR and I was unaware of the possible conflict. I noticed Conflict Alert activated and observed a possible conflict. I advised our Supervisor of a possible loss of separation. Reflecting back; having the sectors split would have been helpful. The complexity increased since the 40 minutes pass from the start of our shift.

Data retrieved from NASA's ASRS site as of July 2013 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.