Zan supervisor reported of a situation where 20 ATD (along track distance) separation was improperly...

Attributes
ACN	1416539
Time
Date	201701
Local Time Of Day	0601-1200
Place
Locale Reference	ZAN.ARTCC
State Reference	AK
Environment
Light	Daylight
Aircraft 1
Make Model Name	Widebody Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 129
Flight Phase	Cruise
Flight Plan	IFR
Aircraft 2
Make Model Name	Widebody Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 129
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Supervisor / CIC Enroute
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 8
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Narrative:

I was off the floor and took the desk. I went up to the controller on sector 11R and noticed he had 4 aircraft showing two separate conflicts. This is the first conflicting pair that I investigated. There were two aircraft. Aircraft X and aircraft Y. One was at FL320 and one was at FL330; I don't remember which one was at FL320. The aircraft were 27 NM apart. Both aircraft were in the sya radar volume and the data blocks auto acquired but neither aircraft was radar identified. The controller climbed the aircraft at FL320 to FL330 to using radar to establish 20 ATD between them. 20 ATD was misapplied. The controller didn't ask either aircraft the distance from the next waypoint to establish 20 miles between them.the aircraft were mach and remained 27NM apart after they left sya radar volume and into nonradar airspace for the next hour until they got into the spy radar volume and radar identified.as recommended in my previous report I would like a briefing item or clarification from airspace the proper way to set up 20 ATD in atop. Can you use radar to establish 20 NM between aircraft or do you need to ask the DME or distance to the next fix/waypoint.

Original NASA ASRS Text

Title: ZAN Supervisor reported of a situation where 20 ATD (Along Track Distance) separation was improperly applied to two aircraft at the same altitude. Controller requested clarification on the proper way to set up ATD separation.

Narrative: I was off the floor and took the desk. I went up to the controller on sector 11R and noticed he had 4 aircraft showing two separate conflicts. This is the first conflicting pair that I investigated. There were two aircraft. Aircraft X and Aircraft Y. One was at FL320 and one was at FL330; I don't remember which one was at FL320. The aircraft were 27 NM apart. Both aircraft were in the SYA radar volume and the data blocks auto acquired but neither aircraft was radar identified. The controller climbed the aircraft at FL320 to FL330 to using radar to establish 20 ATD between them. 20 ATD was misapplied. The controller didn't ask either aircraft the distance from the next waypoint to establish 20 miles between them.The aircraft were Mach and remained 27NM apart after they left SYA radar volume and into nonradar airspace for the next hour until they got into the SPY radar volume and radar identified.As recommended in my previous report I would like a briefing item or clarification from airspace the proper way to set up 20 ATD in ATOP. Can you use radar to establish 20 NM between aircraft or do you need to ask the DME or distance to the next fix/waypoint.

Data retrieved from NASA's ASRS site 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.

Zan supervisor reported of a situation where 20 ATD (along track distance) separation was improperly applied to two aircraft at the same altitude. Controller requested clarification on the proper way to set up ATD separation.