Enroute controller being relieved by another controller adjusted the display range to assist the on-...

Attributes
ACN	1011908
Time
Date	201205
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Aircraft 1
Make Model Name	Regional Jet 700 ER/LR (CRJ700)
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Aircraft 2
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

Narrative:

I was relieving radar controller at the sector during a very busy complex time for traffic. After I logged into the position; the radar controller I relieved stayed behind me to make sure I had the traffic. During this period the radar controller I relieved; trying to help; changed my range to a closer range so we could see the traffic better. My range went from a 100 range to a 65 range. This did help at the time; but I am used to running on a 90-100 range. Therefore I saw the traffic between a CRJ7 and an A319 and believed I had more than 5 miles lateral when I descended the A319 to FL300 in order to start this aircraft down for their destination. Since I was on a 65 range this was not the case. Conflict alert did not go off until I lost separation. I believe this happened because the radar controller I relieved was trying to help; but by doing so; I was put into a situation that I was not used to; i.e. Running traffic on a 65 mile range.

Original NASA ASRS Text

Title: Enroute Controller being relieved by another controller adjusted the display range to assist the on-coming controller with Data Block overlaps; the effort resulting in a loss of separation event.

Narrative: I was relieving RADAR Controller at the Sector during a very busy complex time for traffic. After I logged into the position; the RADAR Controller I relieved stayed behind me to make sure I had the traffic. During this period the RADAR Controller I relieved; trying to help; changed my range to a closer range so we could see the traffic better. My range went from a 100 range to a 65 range. This did help at the time; but I am used to running on a 90-100 range. Therefore I saw the traffic between a CRJ7 and an A319 and believed I had more than 5 miles lateral when I descended the A319 to FL300 in order to start this aircraft down for their destination. Since I was on a 65 range this was not the case. Conflict Alert did not go off until I lost separation. I believe this happened because the RADAR Controller I relieved was trying to help; but by doing so; I was put into a situation that I was not used to; i.e. running traffic on a 65 mile range.

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.

Enroute controller being relieved by another controller adjusted the display range to assist the on-coming controller with data block overlaps; the effort resulting in a loss of separation event.