Narrative:

During a somewhat complex session on sector 32 aircraft X was given a crossing restriction of cross spane at and maintain 16;000 feet and 230 knots. Aircraft Y was in trail of aircraft X and given the same clearance. Aircraft Y was assigned a speed of 290 kts from previous controller and was [closing in] with aircraft X . I assigned aircraft X a speed of 290 kts until spane and then to reduce to 230 knots. Aircraft Y was kept at 290 knots to keep the distance and so the aircraft behind would fall into their spots. When aircraft X reached spane I reduced the speed of aircraft Y to 230 knots to keep the two aircraft doing the same thing. I never observed the 2 aircraft inside the 5 mile halo and never observed the data function that indicates less than 5 miles. This also all happened in 3 mile separation area. I was never briefed before any of this that a heavy aircraft was not capable of 3 mile separation in our 3 mile separation airspace. Management as not yet told me if in fact I had an error with wake turbulence or not. They seem to not be understanding our rules either. They were aware of the event shortly after and have not been able to update me with any information. When the 2 aircraft entered approach control airspace I did observe 5 miles and matched speeds. Prior to reaching 16000 feet at spane my supervisor was standing behind me and mentioned that aircraft Y was not capable of 3 mile separation at that specific time due him being above 23;000 feet. When this was talked about I did have a 3 mile halo on the aircraft X who was below 22;000 feet and clearly in the 3 mile separation airspace. This misunderstanding of using 3 mile airspace with heavy aircraft is not limited to controllers. Management including operations managers have been discussing for 2 days now if this was an error or not. At this time they have not mentioned to me either way other than they were looking into it.as per 7110.65 section 5-5-4 g.g. Separate aircraft operating directly behind or following an aircraft conducting an instrument approach by the minima specified and in accordance with the following:aircraft Y was not operating directly behind an aircraft conducting an instrument approach or following an aircraft conducting an instrument approach. They were both assigned to fly the leehy RNAV arrival but maintain 16;000 feet. This is not an instrument approach. I would recommend some briefing on use of 3 mile airspace if it is not intended for heavy aircraft. I would also recommend that heavy aircraft have some sort of identifier in the data block so as to alert the controller; especially on busy sessions that don't always allow the controller to check every line of flight plan. I would also a recommend that heavy aircraft are not allowed to display a 3 mile halo on so as to not give false sense of security.

Google
 

Original NASA ASRS Text

Title: An Enroute controller reported using three miles in trail separation in an approved environment however the leading aircraft was a Heavy jet requiring 5 miles separation.

Narrative: During a somewhat complex session on Sector 32 Aircraft X was given a crossing restriction of cross SPANE at and maintain 16;000 feet and 230 knots. Aircraft Y was in trail of Aircraft X and given the same clearance. Aircraft Y was assigned a speed of 290 kts from previous controller and was [closing in] with Aircraft X . I assigned Aircraft X a speed of 290 kts until SPANE and then to reduce to 230 knots. Aircraft Y was kept at 290 knots to keep the distance and so the aircraft behind would fall into their spots. When Aircraft X reached SPANE I reduced the speed of Aircraft Y to 230 knots to keep the two aircraft doing the same thing. I never observed the 2 aircraft inside the 5 mile halo and never observed the data function that indicates less than 5 miles. This also all happened in 3 mile separation area. I was never briefed before any of this that a heavy aircraft was not capable of 3 mile separation in our 3 mile separation airspace. Management as not yet told me if in fact I had an error with Wake Turbulence or not. They seem to not be understanding our rules either. They were aware of the event shortly after and have not been able to update me with any information. When the 2 aircraft entered Approach Control airspace I did observe 5 miles and matched speeds. Prior to reaching 16000 feet at SPANE my Supervisor was standing behind me and mentioned that Aircraft Y was not capable of 3 mile separation at that specific time due him being above 23;000 feet. When this was talked about I did have a 3 mile halo on the Aircraft X who was below 22;000 feet and clearly in the 3 mile separation airspace. This misunderstanding of using 3 mile airspace with heavy aircraft is not limited to controllers. Management including Operations Managers have been discussing for 2 days now if this was an error or not. At this time they have not mentioned to me either way other than they were looking into it.As per 7110.65 section 5-5-4 g.g. Separate aircraft operating directly behind or following an aircraft conducting an instrument approach by the minima specified and in accordance with the following:Aircraft Y was not operating directly behind an aircraft conducting an instrument approach or following an aircraft conducting an instrument approach. They were both assigned to fly the LEEHY RNAV arrival but maintain 16;000 feet. This is not an instrument approach. I would recommend some briefing on use of 3 mile airspace if it is not intended for heavy aircraft. I would also recommend that heavy aircraft have some sort of identifier in the data block so as to alert the controller; especially on busy sessions that don't always allow the controller to check every line of flight plan. I would also a recommend that heavy aircraft are not allowed to display a 3 mile halo on so as to not give false sense of security.

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.