Narrative:

Aircraft Y departed anc runway 25R assigned heading 210 climbing to 040. Aircraft X IFR departed anc runway 15 assigned heading of 200. The initial lateral separation was 4 miles; however aircraft X was showing an increasing ground speed compressing with aircraft Y. The north radar controller restricted aircraft X to 020 and turned the aircraft westbound on course. The north radar controller expressed concern over the operation; specifically believing the local controller did not understand divergence and that the operation had the potential to result in a loss of separation. I called the tower to ask what type of separation was being applied between the two departing aircraft; and was informed that the tower had been using lateral separation. The aircraft had never been closer than 4 miles apart in their opinion. I stated that I wanted to make sure that the controller understood that 10 degrees was not sufficient for divergence. The local controller came down to the TRACON on his break asking about the incident. I reiterated that there was no loss of separation; just a concern about the procedure and that it had caused several questions.question: does lateral separation exist if the aircraft before the aircraft is established in radar contact? The radar identified aircraft were not provided radar service until the north radar controller identified the aircraft and issued radar contact.question: aircraft X heading 200 needed to turn to the right for route of flight; aircraft Y heading 210 needed to turn left for route of flight; the faster aircraft was behind. What is the expectation for ensuring constant and increasing separation for the tower and radar controller?there is a lot of confusion between the tower and approach concerning fan headings and dva due to a recent change in the dva. The application of fan headings is not consistent between crews and expectations are not being met on both sides of the issue.

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Original NASA ASRS Text

Title: A11 Controller questions the procedure of ANC departing a slower aircraft before a faster aircraft and what type of separation they were using.

Narrative: Aircraft Y departed ANC Runway 25R assigned heading 210 climbing to 040. Aircraft X IFR departed ANC Runway 15 assigned heading of 200. The initial lateral separation was 4 miles; however Aircraft X was showing an increasing ground speed compressing with Aircraft Y. The North Radar Controller restricted Aircraft X to 020 and turned the aircraft westbound on course. The North Radar Controller expressed concern over the operation; specifically believing the Local Controller did not understand divergence and that the operation had the potential to result in a loss of separation. I called the Tower to ask what type of separation was being applied between the two departing aircraft; and was informed that the Tower had been using lateral separation. The aircraft had never been closer than 4 miles apart in their opinion. I stated that I wanted to make sure that the Controller understood that 10 degrees was not sufficient for divergence. The Local Controller came down to the TRACON on his break asking about the incident. I reiterated that there was no loss of separation; just a concern about the procedure and that it had caused several questions.Question: Does lateral separation exist if the aircraft before the aircraft is established in radar contact? The radar identified aircraft were not provided radar service until the North Radar Controller identified the aircraft and issued radar contact.Question: Aircraft X heading 200 needed to turn to the right for route of flight; Aircraft Y heading 210 needed to turn left for route of flight; the faster aircraft was behind. What is the expectation for ensuring constant and increasing separation for the Tower and Radar Controller?There is a lot of confusion between the Tower and Approach concerning fan headings and DVA due to a recent change in the DVA. The application of fan headings is not consistent between crews and expectations are not being met on both sides of the issue.

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.