A controller reported a cessna was supposed to follow air carrier traffic on short final but turned ...

Narrative:

I was not working at the time of the event. I was told about the event after the fact. After hearing about the event; I watched the replay and realized it was controller error. Aircraft X was initially told on upwind to keep his pattern tight and the controller would try to get him another touch and go ahead of a regional jet. On downwind; the cessna was told to expect to follow the regional jet and report the jet on 4 mile final in-sight. The cessna reported the crj in sight abeam the numbers; and the controller told the cessna 'runway 27 cleared for the option.' the cessna shortly after turned base into the oncoming regional jet. The controller took no action. The regional jet reported the traffic to tower. Tower asked cessna to verify the crj was in sight; cessna affirmed. The regional pilot told the cessna he was not supposed to [turn] base in front of him. Separation was .14 mile and 100 feet. The controller then cleared the cessna for low approach; separation was .06 mile and 100 feet. The cessna got low enough to the runway to drop off the radar; when the controller asked cessna to confirm he was doing a low approach; which the cessna affirmed. I was told that the crj was not clear of the runway while the cessna was doing low approach. Cid does not have asde-X. Ground and local position were split.

Original NASA ASRS Text

Title: A Controller reported a Cessna was supposed to follow Air Carrier traffic on short final but turned into the traffic due to incomplete instructions from the Local Controller.

Narrative: I was not working at the time of the event. I was told about the event after the fact. After hearing about the event; I watched the replay and realized it was controller error. Aircraft X was initially told on upwind to keep his pattern tight and the Controller would try to get him another touch and go ahead of a regional jet. On downwind; the Cessna was told to expect to follow the regional jet and report the jet on 4 mile final in-sight. The Cessna reported the CRJ in sight abeam the numbers; and the Controller told the Cessna 'Runway 27 cleared for the option.' The Cessna shortly after turned base into the oncoming regional jet. The controller took no action. The regional jet reported the traffic to Tower. Tower asked Cessna to verify the CRJ was in sight; Cessna affirmed. The regional pilot told the Cessna he was not supposed to [turn] base in front of him. Separation was .14 mile and 100 feet. The controller then cleared the Cessna for low approach; separation was .06 mile and 100 feet. The Cessna got low enough to the runway to drop off the radar; when the Controller asked Cessna to confirm he was doing a low approach; which the Cessna affirmed. I was told that the CRJ was not clear of the runway while the Cessna was doing low approach. CID does not have ASDE-X. Ground and Local position were split.

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	1668252
Time
Date	201907
Local Time Of Day	0601-1200
Place
Locale Reference	CID.Airport
State Reference	IA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	None
Flight Plan	VFR
Aircraft 2
Make Model Name	Regional Jet 200 ER/LR (CRJ200)
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Other / Unknown
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 2.0
Events
Anomaly	ATC Issue All Types Conflict NMAC Deviation - Procedural Published Material / Policy

A controller reported a cessna was supposed to follow air carrier traffic on short final but turned into the traffic due to incomplete instructions from the local controller.