ZLA controllers described a critical loss of separation event when a data block was dropped of the r...

Attributes
ACN	879176
Time
Date	201003
Local Time Of Day	0001-0600
Place
Locale Reference	ZLA.ARTCC
State Reference	CA
Aircraft 1
Make Model Name	PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Phase	Cruise
Flight Plan	IFR
Aircraft 2
Make Model Name	Cessna Citation Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Climb
Flight Plan	IFR
Person 1
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Instructor
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy

Narrative:

I was at R10 working aircraft X who had been handed off to sector 19 before I sat down. The aircraft was slow and I'm told that the computer dropped the data block; in my airspace; 20 minutes after sector 19 took the hand off. I wasn't aware that this was even a possibility or I might have been watching the data block more closely. Three minutes after the data block dropped off I was relieved and about five minutes after that they had a deal; climbing citation jet through aircraft X. I've seen data blocks drop off when we've handed off to other facilities; but I don't recall ever being told about data blocks dropping off in my airspace because another center sector has radar. Recommendation; obviously; eliminate the auto data block dropping feature.

Original NASA ASRS Text

Title: ZLA Controllers described a critical loss of separation event when a data block was dropped of the RADAR Sector display and not identified as conflicting traffic by several controllers.

Narrative: I was at R10 working Aircraft X who had been handed off to Sector 19 before I sat down. The aircraft was slow and I'm told that the computer dropped the data block; in my airspace; 20 minutes after Sector 19 took the hand off. I wasn't aware that this was even a possibility or I might have been watching the data block more closely. Three minutes after the data block dropped off I was relieved and about five minutes after that they had a deal; climbing Citation Jet through Aircraft X. I've seen data blocks drop off when we've handed off to other facilities; but I don't recall ever being told about data blocks dropping off in my airspace because another Center sector has RADAR. Recommendation; obviously; eliminate the auto data block dropping feature.

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.

ZLA controllers described a critical loss of separation event when a data block was dropped of the radar sector display and not identified as conflicting traffic by several controllers.