Aus approach controller described technical loss of separation when they failed to issue visual appr...

Narrative:

I was working final approach in a moderately busy session. Runway 17R closed to arrivals; putting all aircraft in queue for landing runway 17L. Air carrier X; a heavy jet; was cleared for a visual approach to runway 17L; and switched to tower frequency. Air carrier Y; a CRJ7; was issued traffic on the heavy jet and CRJ7 reported the heavy jet and the airport in sight. I acknowledged the transmission and instructed air carrier Y to maintain 3;000 ft; and issued traffic on a primary target ahead. I never went back and instructed air carrier Y to follow the traffic; and did not issue a wake turbulence advisory. I shipped air carrier Y off to the tower with no clearance for the approach; thinking I had done so. A supervisor approached me and told me that the CRJ7 had an overtake on the heavy jet; and asked me if the aircraft was following the heavy visually. Believing that to be the case; I said yes. As I was working; I tried to replay the scenario in my head; and could not remember issuing a wake turbulence advisory to air carrier Y; so I called the tower and asked the controller to issue the advisory for me; which he did. Air carrier Y had already initiated descent on his own; and was then cleared to land by the tower. After getting relieved from the position; I had time to think about the situation; and could not replay in my head issuing an approach clearance; so I asked to listen to the voice recording. Sure enough; air carrier Y reported the heavy jet in sight; but I did not issue the clearance. The radar showed it was 4.69 miles in trail; of course I needed 5 miles. Altitude was maintained all the way down; although that does not matter in this situation; closest point was 1100 ft vertical when the heavy touched down. In hindsight; when the supervisor approached me I should have acknowledged even the slight possibility that all was not as it should have been and called the tower to reissue the clearance. Since air carrier Y was already following the heavy anyway; just the matter of a few words would have salvaged the situation.

Original NASA ASRS Text

Title: AUS Approach Controller described technical loss of separation when they failed to issue visual approach wake turbulence advisory after trailing air carrier reported heavy traffic in sight and following.

Narrative: I was working final approach in a moderately busy session. Runway 17R closed to arrivals; putting all aircraft in queue for landing Runway 17L. Air Carrier X; a heavy jet; was cleared for a visual approach to Runway 17L; and switched to Tower frequency. Air Carrier Y; a CRJ7; was issued traffic on the heavy jet and CRJ7 reported the Heavy Jet and the airport in sight. I acknowledged the transmission and instructed Air Carrier Y to maintain 3;000 FT; and issued traffic on a primary target ahead. I never went back and instructed Air Carrier Y to follow the traffic; and did not issue a wake turbulence advisory. I shipped Air Carrier Y off to the Tower with no clearance for the approach; thinking I had done so. A Supervisor approached me and told me that the CRJ7 had an overtake on the Heavy Jet; and asked me if the aircraft was following the Heavy visually. Believing that to be the case; I said yes. As I was working; I tried to replay the scenario in my head; and could not remember issuing a wake turbulence advisory to Air Carrier Y; so I called the Tower and asked the Controller to issue the advisory for me; which he did. Air Carrier Y had already initiated descent on his own; and was then cleared to land by the Tower. After getting relieved from the position; I had time to think about the situation; and could not replay in my head issuing an approach clearance; so I asked to listen to the voice recording. Sure enough; Air Carrier Y reported the Heavy Jet in sight; but I did not issue the clearance. The radar showed it was 4.69 miles in trail; of course I needed 5 miles. Altitude was maintained all the way down; although that does not matter in this situation; closest point was 1100 FT vertical when the Heavy touched down. In hindsight; when the Supervisor approached me I should have acknowledged even the slight possibility that all was not as it should have been and called the Tower to reissue the clearance. Since Air Carrier Y was already following the Heavy anyway; just the matter of a few words would have salvaged the situation.

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.

Attributes
ACN	822753
Time
Date	200902
Local Time Of Day	1201-1800
Place
Locale Reference	AUS.Airport
State Reference	TX
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Large Transport
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Visual Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Regional Jet 700 ER/LR (CRJ700)
Flight Phase	Initial Approach
Route In Use	Visual Approach Vectors
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Non Radar 3 Air Traffic Control Radar 21 Air Traffic Control Time Certified In Pos 1 (yrs) 18
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy
Miss Distance	Horizontal 26000 Vertical 1100

Aus approach controller described technical loss of separation when they failed to issue visual approach wake turbulence advisory after trailing air carrier reported heavy traffic in sight and following.