Cle controller reported of a situation where he was not sure as to what type of separation the tower...

Narrative:

Cgf tower called for IFR release on aircraft X. I issued release with a right turn heading 100. As I began a position relief briefing; cgf tower called for another IFR release on aircraft Y. I issued 'visual separation approved between aircraft X and aircraft Y; aircraft Y released heading 210.' as a tower controller myself; I believed that cgf tower would let aircraft X run out for a couple of miles and then release aircraft Y with a turn off the deck inside of aircraft X and maintain tower visual until divergence was established. What cgf tower did was keep aircraft Y on runway heading for nearly 5 miles. The controller who relieved me called to cgf tower to ask them to leave aircraft Y on runway heading. During the call cgf tower informed the relieving controller that aircraft Y was in the turn. I don't recall the relieving controller's response. Aircraft X and aircraft Y's targets merged about 7 mile east of cgf at 030. Aircraft Y checked on to the frequency as the targets were merged saying that he had aircraft X in sight. I don't know at what point aircraft Y got aircraft X in sight or what the cgf tower controllers actions were while aircraft Y was on their frequency. I don't know how to prevent this from happening again. The cgf tower controller and I obviously had very different ideas about how visual separation would be used in this operation. It is possible that aircraft Y had aircraft X in sight before the cgf tower controller turned aircraft Y off of runway heading.

Original NASA ASRS Text

Title: CLE Controller reported of a situation where he was not sure as to what type of separation the Tower was using. Controller reported thinking that the Tower would do what he was thinking; but did not. Aircraft had the other in sight but reporter did not know when this visual separation had happened.

Narrative: CGF tower called for IFR release on Aircraft X. I issued release with a right turn heading 100. As I began a position relief briefing; CGF tower called for another IFR release on Aircraft Y. I issued 'visual separation approved between Aircraft X and Aircraft Y; Aircraft Y released heading 210.' As a tower controller myself; I believed that CGF tower would let Aircraft X run out for a couple of miles and then release Aircraft Y with a turn off the deck inside of Aircraft X and maintain tower visual until divergence was established. What CGF tower did was keep Aircraft Y on runway heading for nearly 5 miles. The controller who relieved me called to CGF tower to ask them to leave Aircraft Y on runway heading. During the call CGF tower informed the relieving controller that Aircraft Y was in the turn. I don't recall the relieving controller's response. Aircraft X and Aircraft Y's targets merged about 7 mile east of CGF at 030. Aircraft Y checked on to the frequency as the targets were merged saying that he had Aircraft X in sight. I don't know at what point Aircraft Y got Aircraft X in sight or what the CGF tower controllers actions were while Aircraft Y was on their frequency. I don't know how to prevent this from happening again. The CGF tower controller and I obviously had very different ideas about how visual separation would be used in this operation. It is possible that Aircraft Y had Aircraft X in sight before the CGF tower controller turned Aircraft Y off of runway heading.

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.

Attributes
ACN	1339008
Time
Date	201603
Local Time Of Day	1801-2400
Place
Locale Reference	CLE.Tower
State Reference	OH
Environment
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft Low Wing 1 Eng Retractable Gear
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Departure Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 1
Events
Anomaly	ATC Issue All Types Conflict NMAC Deviation - Procedural Clearance

Cle controller reported of a situation where he was not sure as to what type of separation the tower was using. Controller reported thinking that the tower would do what he was thinking; but did not. Aircraft had the other in sight but reporter did not know when this visual separation had happened.