TRACON controller experienced a loss of separation when attempting to establish visual separation be...

Attributes
ACN	1111436
Time
Date	201308
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	Gulfstream V / G500 / G550
Operating Under FAR Part	Part 91
Flight Phase	Climb
Flight Plan	IFR
Person 1
Function	Approach Departure
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

Narrative:

An A320 departed on SID X. A GLF5 departed on the SID Y and was instructed to maintain visual separation with the A320 departing before him. The GLF5 failed to maintain visual separation with the departing aircraft because the GLF5 had a greater climb rate than the A320. The GLF5 was leaving 041 as he reported he lost sight of the departing traffic which was at 035. I called traffic and the GLF5 still did not have the A320 in sight. The next transmission was a vector for separation. When the GLF5 reported he lost sight of departing traffic; I should have vectored for separation first and then call traffic. Unfortunately I called traffic first; then vectored for separation.

Original NASA ASRS Text

Title: TRACON Controller experienced a loss of separation when attempting to establish visual separation between two successive departures; the second aircraft climbed faster than the first.

Narrative: An A320 departed on SID X. A GLF5 departed on the SID Y and was instructed to maintain visual separation with the A320 departing before him. The GLF5 failed to maintain visual separation with the departing aircraft because the GLF5 had a greater climb rate than the A320. The GLF5 was leaving 041 as he reported he lost sight of the departing traffic which was at 035. I called traffic and the GLF5 still did not have the A320 in sight. The next transmission was a vector for separation. When the GLF5 reported he lost sight of departing traffic; I should have vectored for separation first and then call traffic. Unfortunately I called traffic first; then vectored for separation.

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.

TRACON controller experienced a loss of separation when attempting to establish visual separation between two successive departures; the second aircraft climbed faster than the first.